using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (a, b, k) = (c[0], c[1], c[2]);
        var lcm = (long)a / GCD(a, b) * b;
        var ok = 1_100_000_000_000_000_000;
        var ng = 0L;
        while (ok - ng > 1)
        {
            var mid = (ok + ng) / 2;
            if (mid / a + mid / b - mid / lcm >= k) ok = mid;
            else ng = mid;
        }
        WriteLine(ok);
    }
    static int GCD(int a, int b)
    {
        if (a < b) return GCD(b, a);
        if (a % b == 0) return b;
        return GCD(b, a % b);
    }
}