#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
typedef long long ll;
#define rep(i,n) for(int i=0;i<(n);i++)
const int mod = 1e9 + 7;
int main(void){
	ll n; cin >> n;
	ll ans = 0;
	rep(i, n){
		ll c, d; cin >> c >> d;
		if(c >= 3){
			(ans += 2 * d) %= mod;
		}else{
			(ans += d) %= mod;
		}
	}
	printf("%d\n", ans % mod);
	return 0;
}