#include <iostream>
using namespace std;

int main(){
  int a,b,k,cnt,i;
  cin >> a >> b >> k;
  cnt = 0;
  i = 1;
  while(true){
    if(i % a == 0 || i % b == 0){
      cnt++;
    }
    if(cnt == k){
      cout << i << endl;
      false;
      break;
    }
    i++;
  }
}