#include<bits/stdc++.h>
#define int long long
using namespace std;
int gcd(int a,int b){return b?gcd(b,a%b):a;}
int lcm(int a,int b){return a/gcd(a,b)*b;}
signed main(){
    int A,B,K;cin>>A>>B>>K;
    int ok=1e18,ng=0;
    while(ok-ng>1){
        int mid=(ok+ng)/2;
        if(mid/A+mid/B-mid/lcm(A,B)<K)ng=mid;
        else ok=mid;
    }
    cout<<ok<<endl;
}