#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <iterator>
#include <cassert>
#include <numeric>
#include <functional>
#include <ctime>
#pragma warning(disable:4996) 

//#define ATCODER
#ifdef ATCODER
#include <atcoder/all>
#endif

typedef long long ll;
typedef unsigned long long ull;
#define LINF  9223300000000000000
#define LINF2 1223300000000000000
#define LINF3 1000000000000
#define INF 2140000000
//const long long MOD = 1000000007;
const long long MOD = 998244353;

using namespace std;
#ifdef ATCODER
using namespace atcoder;
#endif

ll gcd(ll a, ll b) {
    if (b == 0) return a;
    return gcd(b, a%b);
}

ll lcm(ll a, ll b) {
    ll g = gcd(a, b);
    return a / g * b;   // Be careful not to overflow
}

void solve()
{
    ll a, b, K;
    scanf("%lld%lld%lld", &a, &b, &K);
    ll g = lcm(a, b);
    ll l = 0, r = LINF;
    while (r - l > 1) {
        ll m = (l + r) / 2;
        ll tmp = m / a + m / b - m / g;
        if (tmp >= K) {
            r = m;
        }
        else {
            l = m;
        }
    }
    printf("%lld\n", r);
    return;
}

int main()
{
#if 1
    solve();
#else
    int T, t;
    cin >> T;
    for (t = 0; t < T; t++) {
        //cout << "Case #" << t + 1 << ": ";
        solve();
    }
#endif
    return 0;
}