#include <stdio.h>
#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000000
	
int main(){
	
	long long A,B,K;
	cin>>A>>B>>K;
	
	long long ok = 4000000000000000000,ng = 0LL;
	
	while(ok-ng>1){
		long long mid = (ok+ng)/2;
		long long cur = mid/A + mid/B;
		cur -= mid/lcm(A,B);
		
		if(cur>=K)ok = mid;
		else ng = mid;
	}
	
	cout<<ok<<endl;
	
    return 0;
}