#include <bits/stdc++.h>
using namespace std;

int main() {
  long long a, b, c;
  cin>>a>>b>>c;
  long long l = 0, r = ((c - 1) / b + 1) * a;
  while (r - l > 1) {
    long long mid = (l + r) / 2;
    if (mid >= c - (b - 1) * (mid / a)) {
      r = mid;
    } else {
      l = mid;
    }
  }
  if (l >= c - (b - 1) * (l / a)) {
    cout<<l<<endl;
  } else {
    cout<<r<<endl;
  }
}