18781.cpp

#include <bits/stdc++.h>
#define fastio ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)

#define ll long long
using namespace std;

const ll INF = 1e9 + 7;
const ll DIV = (ll)1e9 +7;

ll Pow(ll a, ll r){
    ll ret = 1;
    while(r){
        if(r&1){
            ret = ret * a % DIV;
        }
        a = a * a % DIV;
        r >>= 1;
    }
    return ret;
}

int n;
int arr[202020];
int ok[202020];

int main()
{
    fastio;
    cin >> n;
    for(int i = 0;i< n;i++){
        int a, b;
        cin >> a>> b;
        arr[a]++;
        arr[b]--;
        ok[a]++;
    }

    for(int i = 1;i <= 2*n;i++){
         arr[i] += arr[i - 1];
    }
    
    ll ans = 0;
    for(int i = 1;i<=2*n;i++){
        if(ok[i]){
            ans += Pow(2, n - 1 - arr[i - 1]) ;
            ans %= DIV;
        }
    }
    cout << (ans + DIV)%DIV;
    return 0;
}