#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

int main(void) {
  ll a, b, c;
  cin >> a >> b >> c;

  ll ng = 0, ok = c;
  for (int i = 0; i < 100; i++) {
    ll m = (ng + ok) / 2;
    if (m / a >= (c - m + b - 2) / (b - 1)) ok = m;
    else ng = m;
  }
  cout << ok << endl;

  return 0;
}