#include<bits/stdc++.h>
using namespace std;
int n, a[15], b[15], maxn = 0, maxm;
int main() {
	freopen("ccyz.in", "r", stdin);
	freopen("ccyz.out", "w", stdout);
    cin >> n;
    for(int i = 1; i <= n; i ++) {
        cin >> a[i] >> b[i];
        maxn = max(maxn, a[i]);
        maxm = b[i];
    }
    for(int i = 1; i <= 5000000; i ++) {
    	long long x = i * maxn + maxm;
    	bool f = 1;
    	for(int j = 1; j <= n; j ++) {
    		if(x % a[j] != b[j]) {
    			f = 0;
    			break;
			}
		}
		if(f == 1) {
			cout << x << endl;
			return 0;
		}
	}
    return 0;
}