#include<bits/stdc++.h>
using namespace std;
#define ll long long
signed main(){
    ll n,a[12],b[12];
    cin>>n;
    for(ll q=1;q<=n;q++){
        cin>>a[q]>>b[q];
    }
    ll t=n-1;
    ll i[t+2],j[t+2],k;
    while(t!=0){
        i=a[1]+b[1];
        for(j[t]=1;j[t]<=90000000000000000;j[t]+=i[t]){
            if(j[t]%i[t]==b[t+1]&&j[t]/i[t]==a[t+1]) {
                i==j[t];
                break;
        }
    }
    }
    cout<<i;
    return 0;
}