#include<bits/stdc++.h>
#define int long long
#define INF 0x3f3f3f
using namespace std;
int n,a[100001],b[100001],k,ans;
signed main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);cout.tie(0);
	cin>>n;
	for(int i=1;i<=n;i++)
		cin>>a[i]>>b[i];
	k=a[1],ans=b[1];
	for(int i=2;i<=n;i++){
		while(ans%a[i]!=b[i]%a[i])ans+=k;
		k=k/__gcd(k,a[i])*a[i];
	}
	cout<<ans;
    return 0;
}