#include<bits/stdc++.h>
using namespace std;
#define int unsigned long long
const int INF = 1LL << 60;

signed main(){

  int a, b, c; cin >> a >> b >> c;

  int left = -1, right = INF;
  while(right - left > 1){
    int mid = (left + right) / 2;
    ((mid/a * b) + (mid - mid/a) < c ? left : right) = mid;
  }
  cout << right << endl;

  return 0;
}