#include <cstdio>
#include <cstdlib>
#include <cstddef>
#include <vector>
#include <algorithm>
#include <cmath>
#include <string>
#include <iostream>
#include <iomanip>
#define L64 long long
#define MOD (1000000007LL)

L64 check(L64 age, L64 a, L64 b)
{
  L64 z = age / a;
  return z * b + age - z;
}

int main(void)
{
  L64 a, b, c;
  std::cin >> a >> b >> c;
  L64 min, max;
  min = 0; max = c;
  while(1LL < max - min){
    L64 mid = (min + max) / 2LL;
    L64 score = check(mid, a, b);
    if(score < c){
      min = mid;
    } else {
      max = mid;
    }
  }
  std::cout << max << std::endl;
}