#include <iostream> using namespace std; int f[2000001]; int main() { int n, pos; cin >> n; double a[n]; int t[n]; for (int i=0; i<n; ++i) cin >> a[i] >> t[i]; for (int i=0; i<n; ++i) for (int j=1; j<=t[i]; ++j) { pos = int(j*a[i]); f[pos]=f[pos]?0:1; } for (pos=1;!f[pos];++pos); cout << pos << endl; return 0; }