#include <bits/stdc++.h>
using namespace std;
const long long INF = 1100000000000000000;
long long gcd(long long a, long long b){
  if (b == 0){
    return a;
  } else {
    return gcd(b, a % b);
  }
}
long long lcm(long long a, long long b){
  return a * b / gcd(a, b);
}
int main(){
  long long A, B, K;
  cin >> A >> B >> K;
  long long L = lcm(A, B);
  long long tv = 0, fv = INF;
  while (fv - tv > 1){
    long long mid = (tv + fv) / 2;
    if (mid / A + mid / B - mid / L < K){
      tv = mid;
    } else {
      fv = mid;
    }
  }
  cout << fv << endl;
}