#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 15;
ll a[maxn],b[maxn];
int n;
ll gcd(ll x,ll y) {
    return y ? gcd(y , x % y) : x;
} 
ll lcm(ll x,ll y) {
    return x / gcd(x , y) * y;
}
int main() {
    freopen("ccyz.in","r",stdin);
    freopen("ccyz.out","w",stdout);
    scanf("%d",&n);
    for(int i = 1;i <= n;++ i)scanf("%lld %lld",&a[i],&b[i]);
    ll ans = b[1],tot = a[1];
    for(int i = 2;i <= n;++ i) {
        while(ans % a[i] != b[i]) {
            ans += tot;
        }
        tot = lcm(tot , a[i]);
    }
    printf("%lld",ans);
    return 0;
}