#include <bits/stdc++.h>   using namespace std;   const int maxx = 1e2 + 10;   int a[maxx], b[maxx];   int n;   inline bool check(int m) {     int max1 = 0, max2 = 0;     for (int i = 1; i <= n; i++) {       if (a[i] && !b[i])         max1 += m;       else if (a[i] && b[i])         max1 += 1, max2 += 1;       else if (!a[i] && b[i])         max2 += 1;       else         ;     }     return max1 > max2;   }   int main() {     while (cin >> n && n) {       for (int i = 1; i <= n; i++) cin >> a[i];       for (int i = 1; i <= n; i++) cin >> b[i];       int l = 1, r = 1e7, mid;       int ans = -1;       while (l <= r) {         mid = l + r >> 1;         if (check(mid)) {           ans = mid;           r = mid - 1;         } else           l = mid + 1;       }       cout << ans << endl;     }     return 0;   }   