#include <iostream>
using namespace std;
int main()
{
	int n;
	cin >> n;
	int div[n],mod[n];
	for (int i = 0; i < n; i++) cin >> div[i] >> mod[i];
	for (int i = 1;; i++)
	{
		if (i % div[0] == mod[0] && i % div[1] == mod[1] && i % div[2] == mod[2])
		{
			cout << i << endl;
			return 0;
		}
	}
} 
//#1 #3 #4      TLE
//#2 #5 #6 #8 #9  WA
//#7 #10       AC