#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <iomanip>
#include <cmath>
#include <functional>
using namespace std;
#define diff(x,y) ((x > y) ? (x - y) : (y - x))
#define us(x) ((x > 0) ? x : x * -1)
#define change(x) (x ? false : true)
#define rep(i, n) for (int i = 0; i < (n); i++)
#define lli long long int
const lli mod = 1e9 + 7;


int main() {
	lli n, x, y, ans = 0;
	cin >> n;
	rep(i,n){
		cin >> x >> y;
		x++;
		ans += (x / 2) % mod * (y % mod) % mod;
		ans %= mod;
	}
	cout << ans << endl;
	return 0;
}