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#include <bits/stdc++.h>
using namespace std;
//{
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define FORD(i, a, b) for(int i = (a); i >= (b); --i)
#define VAR(v, i) __typeof(i) v=(i)
#define all(v) (v).begin(),(v).end()
#define FORE(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)


#define PII pair<int,int>
#define st first
#define nd second
#define pb push_back
#define lint long long int
#define VI vector<int>

#define sim template < class c
#define ris return * this
#define dor > debug & operator <<
#define eni(x) sim > typename \
  enable_if<sizeof dud<c>(0) x 1, debug&>::type operator<<(c i) {
sim > struct rge { c b, e; };
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c* x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
~debug() { cerr << endl; }
eni(!=) cerr << boolalpha << i; ris; }
eni(==) ris << range(begin(i), end(i)); }
sim, class b dor(pair < b, c > d) {
  ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
  *this << "[";
  for (auto it = d.b; it != d.e; ++it)
	*this << ", " + 2 * (it == d.b) << *it;
  ris << "]";
}
};
//{
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

#define make( x) int (x); scanf("%d",&(x));
#define make2( x, y) int (x), (y); scanf("%d%d",&(x),&(y));
#define make3(x, y, z) int (x), (y), (z); scanf("%d%d%d",&(x),&(y),&(z));
#define make4(x, y, z, t) int (x), (y), (z), (t); scanf("%d%d%d%d",&(x),&(y),&(z),&(t));
#define makev(v,n) VI (v); FOR(i,0,(n)) { make(a); (v).pb(a);} 
#define IOS ios_base::sync_with_stdio(0)
#define HEAP priority_queue

#define read( x) scanf("%d",&(x));
#define read2( x, y) scanf("%d%d",&(x),&(y));
#define read3(x, y, z) scanf("%d%d%d",&(x),&(y),&(z));
#define read4(x, y, z, t) scanf("%d%d%d%d",&(x),&(y),&(z),&(t));
#define readv(v,n) FOR(i,0,(n)) { make(a); (v).pb(a);}
#define jeb() fflush(stdout);
//}

int mod = 1e9 + 7;

vector<PII> v;
int inv[500005];
int nad[1000005];
int anc[500005];
VI dol[500005];

int main() {
	make(n);
	inv[1] = 1;
	FOR(i,2,n+1) {
		int q = mod / i ;
		int r = mod - q * i;
		inv[i] = ((mod - q) * 1LL * inv[r])%mod;
	}
	FOR(i,0,n) {
		make2(a, b); a--; b--;
		v.pb({a,b});
	}
	// mamy DAG odpowiedz to suma 1/(#poprzednicy(v) + 1)
	// dla ogolnego daga nie ma algosa :(
	// trzeba jakos wykorzystac strukture
	FOR(i,0,2*n) {
		nad[i] = -1;
		if (i < n) anc[i] = 0;
	}
	FOR(i,0,n) {
		int a = v[i].st, b = v[i].nd;
		if (nad[a] == -1 && nad[b] != -1) {
			dol[i] = dol[nad[b]];
		} else if (nad[a] != -1 && nad[b] == -1) {
			dol[i] = dol[nad[a]];
		} else if (nad[a] != -1 && nad[b] != -1) {
			int i1 = 0, i2 = 0;
			int p1 = nad[a], p2 = nad[b];
			while (i1 < dol[p1].size() && i2 < dol[p2].size()) {
				if (dol[p1][i1] < dol[p2][i2]) {
					dol[i].pb(dol[p1][i1]); i1++;
				} else if (dol[p1][i1] > dol[p2][i2]) {
					dol[i].pb(dol[p2][i2]); i2++;
				} else if (dol[p1][i1] == dol[p2][i2]) {
					dol[i].pb(dol[p1][i1]); i1++; i2++;
				}
			}
			FOR(ii,i1,dol[p1].size()) dol[i].pb(dol[p1][ii]);
			FOR(ii,i2,dol[p2].size()) dol[i].pb(dol[p2][ii]);
		} 
		dol[i].pb(i);
		FOR(j,0,dol[i].size()) {
			anc[dol[i][j]]++;
		}
		FOR(j,a,b+1) nad[j] = i; 
	}

	int ans = 0;
	FOR(i,0,n) {
		ans = ans + inv[anc[i]];
		if (ans >= mod) ans -= mod;
	}
	printf("%d\n", ans);

}