using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace foryuki
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] s = Console.ReadLine().Split();
            long A = long.Parse(s[0]);
            long B = long.Parse(s[1]);
            long T = long.Parse(s[2]);
            var d = long.MaxValue;

            long x = 0;
            long y = 0;



            while (x < T)
            {
                y = x;


                while (y < T)
                {
                    y += A;
                }
                if (y < d)
                {
                    d = y;
                }
                x += B;
            }

            if (x < d)
            {
                d = x;
            }

            Console.WriteLine(d);
        }

        //-------------------------------------------------------------

        static int[] ConvertStringArrayToIntArray(string[] array)
        {
            return Array.ConvertAll(array, str => int.Parse(str));
        }

        static List<int> ConvertStringArrayToIntList(string[] str)
        {
            var list = new List<int>();
            foreach (var c in str) list.Add(int.Parse(c));
            return list;
        }
    }
}