#include <bits/stdc++.h>
using namespace std;

// przekopiowane z https://gist.github.com/ar-pa/957297fb3f88996ead11
/*
  ######################################################################
  #######################   THE   BIG   INT   ##########################
*/
const int base = 1000000000;
const int base_digits = 9; 
struct bigint {
	vector<int> a;
	int sign;
	/*<arpa>*/
	int size(){
		if(a.empty())return 0;
		int ans=(a.size()-1)*base_digits;
		int ca=a.back();
		while(ca)
			ans++,ca/=10;
		return ans;
	}
	bigint operator ^(const bigint &v){
		bigint ans=1,a=*this,b=v;
		while(!b.isZero()){
			if(b%2)
				ans*=a;
			a*=a,b/=2;
		}
		return ans;
	}
	string to_string(){
		stringstream ss;
		ss << *this;
		string s;
		ss >> s;
		return s;
	}
	int sumof(){
		string s = to_string();
		int ans = 0;
		for(auto c : s)  ans += c - '0';
		return ans;
	}
	/*</arpa>*/
	bigint() :
		sign(1) {
	}
 
	bigint(long long v) {
		*this = v;
	}
 
	bigint(const string &s) {
		read(s);
	}
 
	void operator=(const bigint &v) {
		sign = v.sign;
		a = v.a;
	}
 
	void operator=(long long v) {
		sign = 1;
		a.clear();
		if (v < 0)
			sign = -1, v = -v;
		for (; v > 0; v = v / base)
			a.push_back(v % base);
	}
 
	bigint operator+(const bigint &v) const {
		if (sign == v.sign) {
			bigint res = v;
 
			for (int i = 0, carry = 0; i < (int) max(a.size(), v.a.size()) || carry; ++i) {
				if (i == (int) res.a.size())
					res.a.push_back(0);
				res.a[i] += carry + (i < (int) a.size() ? a[i] : 0);
				carry = res.a[i] >= base;
				if (carry)
					res.a[i] -= base;
			}
			return res;
		}
		return *this - (-v);
	}
 
	bigint operator-(const bigint &v) const {
		if (sign == v.sign) {
			if (abs() >= v.abs()) {
				bigint res = *this;
				for (int i = 0, carry = 0; i < (int) v.a.size() || carry; ++i) {
					res.a[i] -= carry + (i < (int) v.a.size() ? v.a[i] : 0);
					carry = res.a[i] < 0;
					if (carry)
						res.a[i] += base;
				}
				res.trim();
				return res;
			}
			return -(v - *this);
		}
		return *this + (-v);
	}
 
	void operator*=(int v) {
		if (v < 0)
			sign = -sign, v = -v;
		for (int i = 0, carry = 0; i < (int) a.size() || carry; ++i) {
			if (i == (int) a.size())
				a.push_back(0);
			long long cur = a[i] * (long long) v + carry;
			carry = (int) (cur / base);
			a[i] = (int) (cur % base);
			//asm("divl %%ecx" : "=a"(carry), "=d"(a[i]) : "A"(cur), "c"(base));
		}
		trim();
	}
 
	bigint operator*(int v) const {
		bigint res = *this;
		res *= v;
		return res;
	}
 
	void operator*=(long long v) {
		if (v < 0)
			sign = -sign, v = -v;
		if(v > base){
			*this = *this * (v / base) * base + *this * (v % base);
			return ;
		}
		for (int i = 0, carry = 0; i < (int) a.size() || carry; ++i) {
			if (i == (int) a.size())
				a.push_back(0);
			long long cur = a[i] * (long long) v + carry;
			carry = (int) (cur / base);
			a[i] = (int) (cur % base);
			//asm("divl %%ecx" : "=a"(carry), "=d"(a[i]) : "A"(cur), "c"(base));
		}
		trim();
	}
 
	bigint operator*(long long v) const {
		bigint res = *this;
		res *= v;
		return res;
	}
 
	friend pair<bigint, bigint> divmod(const bigint &a1, const bigint &b1) {
		int norm = base / (b1.a.back() + 1);
		bigint a = a1.abs() * norm;
		bigint b = b1.abs() * norm;
		bigint q, r;
		q.a.resize(a.a.size());
 
		for (int i = a.a.size() - 1; i >= 0; i--) {
			r *= base;
			r += a.a[i];
			int s1 = r.a.size() <= b.a.size() ? 0 : r.a[b.a.size()];
			int s2 = r.a.size() <= b.a.size() - 1 ? 0 : r.a[b.a.size() - 1];
			int d = ((long long) base * s1 + s2) / b.a.back();
			r -= b * d;
			while (r < 0)
				r += b, --d;
			q.a[i] = d;
		}
 
		q.sign = a1.sign * b1.sign;
		r.sign = a1.sign;
		q.trim();
		r.trim();
		return make_pair(q, r / norm);
	}
 
	bigint operator/(const bigint &v) const {
		return divmod(*this, v).first;
	}
 
	bigint operator%(const bigint &v) const {
		return divmod(*this, v).second;
	}
 
	void operator/=(int v) {
		if (v < 0)
			sign = -sign, v = -v;
		for (int i = (int) a.size() - 1, rem = 0; i >= 0; --i) {
			long long cur = a[i] + rem * (long long) base;
			a[i] = (int) (cur / v);
			rem = (int) (cur % v);
		}
		trim();
	}
 
	bigint operator/(int v) const {
		bigint res = *this;
		res /= v;
		return res;
	}
 
	int operator%(int v) const {
		if (v < 0)
			v = -v;
		int m = 0;
		for (int i = a.size() - 1; i >= 0; --i)
			m = (a[i] + m * (long long) base) % v;
		return m * sign;
	}
 
	void operator+=(const bigint &v) {
		*this = *this + v;
	}
	void operator-=(const bigint &v) {
		*this = *this - v;
	}
	void operator*=(const bigint &v) {
		*this = *this * v;
	}
	void operator/=(const bigint &v) {
		*this = *this / v;
	}
 
	bool operator<(const bigint &v) const {
		if (sign != v.sign)
			return sign < v.sign;
		if (a.size() != v.a.size())
			return a.size() * sign < v.a.size() * v.sign;
		for (int i = a.size() - 1; i >= 0; i--)
			if (a[i] != v.a[i])
				return a[i] * sign < v.a[i] * sign;
		return false;
	}
 
	bool operator>(const bigint &v) const {
		return v < *this;
	}
	bool operator<=(const bigint &v) const {
		return !(v < *this);
	}
	bool operator>=(const bigint &v) const {
		return !(*this < v);
	}
	bool operator==(const bigint &v) const {
		return !(*this < v) && !(v < *this);
	}
	bool operator!=(const bigint &v) const {
		return *this < v || v < *this;
	}
 
	void trim() {
		while (!a.empty() && !a.back())
			a.pop_back();
		if (a.empty())
			sign = 1;
	}
 
	bool isZero() const {
		return a.empty() || (a.size() == 1 && !a[0]);
	}
 
	bigint operator-() const {
		bigint res = *this;
		res.sign = -sign;
		return res;
	}
 
	bigint abs() const {
		bigint res = *this;
		res.sign *= res.sign;
		return res;
	}
 
	long long longValue() const {
		long long res = 0;
		for (int i = a.size() - 1; i >= 0; i--)
			res = res * base + a[i];
		return res * sign;
	}
 
	friend bigint gcd(const bigint &a, const bigint &b) {
		return b.isZero() ? a : gcd(b, a % b);
	}
	friend bigint lcm(const bigint &a, const bigint &b) {
		return a / gcd(a, b) * b;
	}
 
	void read(const string &s) {
		sign = 1;
		a.clear();
		int pos = 0;
		while (pos < (int) s.size() && (s[pos] == '-' || s[pos] == '+')) {
			if (s[pos] == '-')
				sign = -sign;
			++pos;
		}
		for (int i = s.size() - 1; i >= pos; i -= base_digits) {
			int x = 0;
			for (int j = max(pos, i - base_digits + 1); j <= i; j++)
				x = x * 10 + s[j] - '0';
			a.push_back(x);
		}
		trim();
	}
 
	friend istream& operator>>(istream &stream, bigint &v) {
		string s;
		stream >> s;
		v.read(s);
		return stream;
	}
 
	friend ostream& operator<<(ostream &stream, const bigint &v) {
		if (v.sign == -1)
			stream << '-';
		stream << (v.a.empty() ? 0 : v.a.back());
		for (int i = (int) v.a.size() - 2; i >= 0; --i)
			stream << setw(base_digits) << setfill('0') << v.a[i];
		return stream;
	}
 
	static vector<int> convert_base(const vector<int> &a, int old_digits, int new_digits) {
		vector<long long> p(max(old_digits, new_digits) + 1);
		p[0] = 1;
		for (int i = 1; i < (int) p.size(); i++)
			p[i] = p[i - 1] * 10;
		vector<int> res;
		long long cur = 0;
		int cur_digits = 0;
		for (int i = 0; i < (int) a.size(); i++) {
			cur += a[i] * p[cur_digits];
			cur_digits += old_digits;
			while (cur_digits >= new_digits) {
				res.push_back(int(cur % p[new_digits]));
				cur /= p[new_digits];
				cur_digits -= new_digits;
			}
		}
		res.push_back((int) cur);
		while (!res.empty() && !res.back())
			res.pop_back();
		return res;
	}
 
	typedef vector<long long> vll;
 
	static vll karatsubaMultiply(const vll &a, const vll &b) {
		int n = a.size();
		vll res(n + n);
		if (n <= 32) {
			for (int i = 0; i < n; i++)
				for (int j = 0; j < n; j++)
					res[i + j] += a[i] * b[j];
			return res;
		}
 
		int k = n >> 1;
		vll a1(a.begin(), a.begin() + k);
		vll a2(a.begin() + k, a.end());
		vll b1(b.begin(), b.begin() + k);
		vll b2(b.begin() + k, b.end());
 
		vll a1b1 = karatsubaMultiply(a1, b1);
		vll a2b2 = karatsubaMultiply(a2, b2);
 
		for (int i = 0; i < k; i++)
			a2[i] += a1[i];
		for (int i = 0; i < k; i++)
			b2[i] += b1[i];
 
		vll r = karatsubaMultiply(a2, b2);
		for (int i = 0; i < (int) a1b1.size(); i++)
			r[i] -= a1b1[i];
		for (int i = 0; i < (int) a2b2.size(); i++)
			r[i] -= a2b2[i];
 
		for (int i = 0; i < (int) r.size(); i++)
			res[i + k] += r[i];
		for (int i = 0; i < (int) a1b1.size(); i++)
			res[i] += a1b1[i];
		for (int i = 0; i < (int) a2b2.size(); i++)
			res[i + n] += a2b2[i];
		return res;
	}
 
	bigint operator*(const bigint &v) const {
		vector<int> a6 = convert_base(this->a, base_digits, 6);
		vector<int> b6 = convert_base(v.a, base_digits, 6);
		vll a(a6.begin(), a6.end());
		vll b(b6.begin(), b6.end());
		while (a.size() < b.size())
			a.push_back(0);
		while (b.size() < a.size())
			b.push_back(0);
		while (a.size() & (a.size() - 1))
			a.push_back(0), b.push_back(0);
		vll c = karatsubaMultiply(a, b);
		bigint res;
		res.sign = sign * v.sign;
		for (int i = 0, carry = 0; i < (int) c.size(); i++) {
			long long cur = c[i] + carry;
			res.a.push_back((int) (cur % 1000000));
			carry = (int) (cur / 1000000);
		}
		res.a = convert_base(res.a, 6, base_digits);
		res.trim();
		return res;
	}
};
/*
  #######################   THE   BIG   INT   ##########################
  ######################################################################
*/
// koniec przekopiowanego

#define ll long long

constexpr int maxn = 5e5+2;
constexpr int M = (1<<20);
constexpr ll mod = 1e9+7;

int n, q1,q2,pl,pr, dp[maxn]; // w dp[i] jest o 1 za duzo ale to nie problem
bigint licz,mian,gc,lc, res, b2;
vector <int> con[maxn], order;
bitset <maxn> vis;

void dfs(int v)
{
	vis[v] = 1; dp[v]++;
	for(auto u : con[v])
		if(!vis[u]) dfs(u);
}

struct
{
	int tree[2*M], lazy[2*M];

	void push(int v)
	{
		if(lazy[v])
		{
			tree[v*2] = lazy[v];
			tree[v*2+1] = lazy[v];
			lazy[v*2] = lazy[v];
			lazy[v*2+1] = lazy[v];
			lazy[v] = 0;
		}
	}

	void update(int val, int a, int b, int l=0, int r=M-1, int v=1)
	{
		if(r < a || l > b) return;
		if(l >= a && r <= b)
		{
			tree[v] = val;
			lazy[v] = val;
			return;
		}

		push(v);

		int mid = (l+r)/2;
		update(val, a, b, l, mid, v*2);
		update(val, a, b, mid+1, r, v*2+1);

		tree[v] = max(tree[v*2], tree[v*2+1]);
	}

	int query(int a, int l=0, int r=M-1, int v=1)
	{
		if(l > a || r < a) return 0;
		if(l >= a && r <= a) return tree[v];

		push(v);

		int mid=(l+r)/2;
		return max(query(a,l,mid,v*2), query(a,mid+1,r,v*2+1));
	}
}seg;

void dod(int x)
{
	b2 = (bigint)x;
	lc = mian*b2/gcd(mian, b2);
	licz = ((lc/b2)+(lc/mian)*licz);
	mian = lc;
	gc = gcd(licz,mian);
	licz /= gc; mian /= gc;
}

bigint fpow(bigint x, ll w)
{
	bigint ret = 1;
	while(w)
	{
		if(w&1) ret = (ret*x)%mod;
		x = (x*x) % mod;
		w /= 2;
	}
	return ret;
}

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);

	cin >> n;
	for(int i=1; i<=n; i++)
	{
		cin >> pl >> pr;
		q1 = seg.query(pl);
		q2 = seg.query(pr);
		if(q1) con[i].push_back(q1);
		if(q2 && (q1 != q2)) con[i].push_back(q2);
		seg.update(i, pl, pr);
	}

	for(int i=1; i<=n; i++)
	{
		dfs(i);
		for(int j=1; j<=i; j++) vis[j] = 0;
	}

	licz = 0; mian = 1;
	for(int i=1; i<=n; i++) dod(dp[i]);

	licz = licz%mod;
	res = (licz*fpow(mian, mod-2)) % mod;
	cout << res << '\n';
}