#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (int)(n); i++)

using namespace std;
using LL = long long;
using P = pair<int,int>;
const LL INF = 5e18;

int main(){
  LL A, B, K;
  cin >> A >> B >> K;
  LL left = 1, right = INF;
  while(right - left > 1){
  	LL mid = (left + right) / 2;
  	LL res = mid / A + mid / B - mid / (A * B / gcd(A, B));
  	if(res >= K) right = mid;
  	else left = mid;
  }
  cout << right << endl;

  return 0;
}