using System;
using System.Collections.Generic;
using System.Linq;

class Solution
{
    internal struct State
    {
        internal int Cost;
        internal int Length;
        internal int CopiedLength;

        internal State(int c, int l, int cl)
        {
            Cost = c;
            Length = l;
            CopiedLength = cl;
        }
    }

    static void Main()
    {
        var n = int.Parse(Console.ReadLine());
        var vals = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
        var c = vals[0];
        var v = vals[1];

        // cost -> length, copied length
        var states = new List<State>() { { new State(0, 1, 0) } };

        State best = states[0];
        while (states.Count > 0)
        {
            var cur = states.OrderBy(s => s.Cost).First();
            states.Remove(cur);

            if (cur.Length >= n)
            {
                best = cur;
                break;
            }

            // copy
            states.Add(new State(cur.Cost + c, cur.Length, cur.Length));
            // paste
            states.Add(new State(cur.Cost + v, cur.Length + cur.CopiedLength, cur.CopiedLength));
        }

        Console.WriteLine(best.Cost);
    }
}