#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("YES");}else{puts("NO");}
#define MAX_N 200005

int main() {
    ll a, b, k;
    cin >> a >> b >> k;

    if(a == b){
        cout << a * k << endl;
        return 0;
    }

    ll l = 0, r = 1001001001001001001;
    while(l+1<r){
        ll m = (l+r) / 2;
        ll cnt = m / a + m / b - m / (a*b);
        if(cnt >= k) r = m;
        else l = m;
    }

    cout << r << endl;
    return 0;
}