#include <bits/stdc++.h>   using namespace std;   int main() {     int a, b, c;     while (cin >> a >> b >> c) {       long long l = 0, r = 100000000;       while (l <= r) {         long long t = (l + r) / 2;         long long w = b * t;         long long d = b * t;         bool ok = true;         while (d < a * c) {           if (w < a) {             ok = false;             break;           }           w -= a;           w += b;           d += b;         }         if (ok)           r = t - 1;         else           l = t + 1;       }       cout << l - 1 << endl;     }     return 0;   }   