#include <bits/stdc++.h>
using namespace std;

int main(){
    long long A, B, C, ng = 0, ok = 1ll << 60, mid;
    cin >> A >> B >> C;
    while(ng + 1 < ok){
        mid = (ng + ok) / 2;
        long long v = mid - mid / A;
        v += min(mid / A, (1ll << 61) / B) * B;
        if(v >= C)ok = mid;
        else ng = mid;
    }
    cout << ok << '\n';
}