最后一个点WA了，求条（悬官）。

#include <bits/stdc++.h>
using namespace std;
const int N = 15;
unsigned long long n, a[N], m[N], MM = 1, M[N], ans;

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin >> n;
	for (int i = 1; i <= n; i++)
		cin >> m[i] >> a[i], MM *= m[i];
	for (int i = 1; i <= n; i++) {
		unsigned long long j = MM / m[i];
		while (j % m[i] != 1 && m[i] != 1)
			j += MM / m[i];
		ans += j * a[i] % MM;
	}
	cout << ans % MM;
	return 0;
}