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#include "bits/stdc++.h"
using namespace std;
#define all(x) x.begin(),x.end()
template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) { return os << p.first << " " << p.second; }
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) { string sep; for (const T &x : v) os << sep << x, sep = " "; return os; }
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#define ASSERT(...) 42
#endif
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pi;
const int oo = 1e9;
struct LCA {
    vi par,d,jmp,in,out;
    vector<basic_string<int>> adj;
    int root;
    LCA(int n,int root=0) : par(n,root),d(n),jmp(n,root),in(n),out(n),adj(n),root(root) {}
    void add(int i) {
        int p = par[i];
        d[i]=1+d[p];
        if(d[p] - d[jmp[p]] == d[jmp[p]] - d[jmp[jmp[p]]]) jmp[i] = jmp[jmp[p]];
        else jmp[i] = p;
    }
    int jump(int a, int k) {
        int D = max(0,d[a]-k);
        while(d[a]>D) {
            if(d[jmp[a]]>=D) a = jmp[a];
            else a = par[a];
        }
        return a;
    }
    template<typename F> pi find(int a, F f) {
        int steps=d[a];
        while(!f(a)) {
            if(!f(jmp[a])) a = jmp[a];
            else a = par[a];
        }
        steps-=d[a]-1;
        return {a,steps};
    }
    int lca(int a, int b) {
        if(d[a]<d[b]) swap(a,b);
        a = jump(a,d[a]-d[b]);
        while(a!=b) {
            if(jmp[a]!=jmp[b]) a=jmp[a],b=jmp[b];
            else a=par[a],b=par[b];
        }
        return a;
    }
    void addE(int u, int v) {
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    int cnt=0;
    void dfs(int at) {
        in[at]=cnt++;
        for(int to: adj[at]) if(to!=par[at])  {
            par[to]=at;
            add(to);
            dfs(to);
        }
        out[at]=cnt;
    }
    void init() {
        dfs(root);
    }
};
const long long MD = 1e9+7;
template<long long MOD=MD> struct mdint {
    int d;
    mdint () {d=0;}
    mdint (long long _d) : d(_d%MOD){
        if(d<0) d+=MOD;
    };
    friend mdint& operator+=(mdint& a, const mdint& o) {
        a.d+=o.d; if(a.d>=MOD) a.d-=MOD;
        return a;
    }
    friend mdint& operator-=(mdint& a, const mdint& o) {
        a.d-=o.d; if(a.d<0) a.d+=MOD;
        return a;
    }
    friend mdint& operator*=(mdint& a, const mdint& o) {
        return a = mdint((ll)a.d*o.d);
    }
    mdint operator*(const mdint& o) const {
        mdint res = *this;
        res*=o;
        return res;
    }
    mdint operator+(const mdint& o) const {
        mdint res = *this;
        res+=o;
        return res;
    }
    mdint operator-(const mdint& o) const {
        mdint res = *this;
        res-=o;
        return res;
    }
    mdint operator^(long long b) const {
        mdint tmp = 1;
        mdint power = *this;
        while(b) {
            if(b&1) {
                tmp = tmp*power;
            }
            power = power*power;
            b/=2;
        }
        return tmp;
    }
    friend mdint operator/=(mdint& a, const mdint& o) {
        a *= (o^(MOD-2));
        return a;
    }
    mdint operator/(const mdint& o) {
        mdint res = *this;
        res/=o;
        return res;
    }
    bool operator==(const mdint& o) { return d==o.d;}
    bool operator!=(const mdint& o) { return d!=o.d;}
    friend istream& operator>>(istream& c, mdint& a) {return c >> a.d;}
    friend ostream& operator<<(ostream& c, const mdint& a) {return c << a.d;}
};
using  mint = mdint<MD>;
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n; cin >> n;
    vector<array<int,2>> lr(n),par(n+1);
    for(auto& [l,r] : lr) cin >> l >> r;
    reverse(all(lr));
    lr.push_back({-oo,oo});
    map<int,pair<int,bool>> mp;
    n++;
    for(int i=0;i<n;++i) {
        auto [l,r] = lr[i];
        auto it = mp.lower_bound(l);
        while(it!=mp.end() and it->first<=r) {
            auto [v,b] = it->second;
            par[v][b]=i;
            it = mp.erase(it);
        }
        mp[l]={i,0};
        mp[r]={i,1};
    }
    LCA lcal(n,n-1),lcar(n,n-1);
    for(int i=0;i<n-1;++i) {
        lcal.addE(i,par[i][0]);
        lcar.addE(i,par[i][1]);
    }
    lcal.init();
    lcar.init();
    vector<unsigned int> reaches(n);
    for(int i=0;i<n-1;++i) {
        reaches[i]++;
        reaches[par[i][0]]+=reaches[i];
        reaches[par[i][1]]+=reaches[i];
        int u=par[i][0],v=par[i][1];
        while(lr[u][1]<lr[v][0]) {
            int ju = lcar.jmp[u], jv = lcal.jmp[v];
            if(lr[ju][1]<lr[jv][0]) {
                if(ju<jv) {
                    u=ju;
                } else v=jv;
            } else if(ju<v and lr[ju][1]<lr[v][0]) {
                u=ju;
            } else if(jv<u and lr[u][1]<lr[jv][0]) {
                v=jv;
            } else if(u<v) {
                u=lcar.par[u];
            } else v = lcal.par[v];
        }
        reaches[max(u,v)]-=reaches[i]; // not double count.
        
    }
    mint ans=0;
    for(int i=0;i<n-1;++i) {
        
        ans+=mint(1)/(reaches[i]);
        // reaches[i]--;
    }
    cout << ans << '\n';
    
}