#include <bits/stdc++.h> 
using namespace std;
const int N = 0;
int n;
int a[20],b[20];
unsigned long long s,ss;
int main(){
    freopen("ccyz.in","r",stdin);
    freopen("ccyz.out","w",stdout);
    scanf("%d",&n);
    for(int i = 1;i <= n;i++){
        scanf("%d%d",&a[i],&b[i]);
    }
    ss = a[1];
    s = a[1] + b[1];
    for(int i = 2;i <= n;i++){
        while((s - b[i]) % a[i]){
            s += ss;
        }
        ss *= a[i];
    }
    cout<<s<<endl;
    
    return 0;
}