using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Text;
using System.Text.RegularExpressions;
using System.Linq;
using System.IO;

class Program
{
    static void Main()
    {
        new Magatro().Solve();
    }
}

class Magatro
{

    private int A, B, T;

    private void Scan()
    {
        var line = Console.ReadLine().Split(' ');
        A = int.Parse(line[0]);
        B = int.Parse(line[1]);
        T = int.Parse(line[2]);
    }

    public void Solve()
    {
        Scan();
        int ans = int.MaxValue;
        for(int i = 0; i <= (T + A - 1) / A; i++)
        {
            int aa = A * i;
            int bb = ((T - A * i + B - 1) / B) * B;
            ans = Math.Min(ans, aa + bb);
            if(ans == T)
            {
                break;
            }
        }
        Console.WriteLine(ans);
    }
}