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

class Program
{
    static int NN => int.Parse(ReadLine());
    static long[] NList => ReadLine().Split().Select(long.Parse).ToArray();
    static void Main()
    {
        var c = NList;
        var (n, a, b) = (c[0], c[1], c[2]);
        var res = a * (n - 1) - b * n;
        if (n % 2 == 0)
        {
            var dbl = n / 2 - 1;
            if (a * 2 > b) res += (b - a * 2) * dbl * 2;
            if (a > b) res += (b - a) * 2;
        }
        else
        {
            var dbl = n / 2;
            if (a * 2 > b) res += (b - a * 2) * dbl * 2;
        }
        WriteLine(res);
    }
}