#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)

bool checkLt(L64 age, L64 a, L64 b, L64 c)
{
  L64 z = age / a;
  //L64 x = z * b + age - z;
  //return x < c;
  //z * b < c - age + z
  if((c - age + z) % b == 0){
    return z < (c - age + z) / b;
  } else {
    return z <= (c - age + z) / b;
  }
}

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;
    bool ret = checkLt(mid, a, b, c);
    if(ret){
      min = mid;
    } else {
      max = mid;
    }
  }
  std::cout << max << std::endl;
}