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

class Program
{
    static int NN => int.Parse(ReadLine());
    static long[] NList => ReadLine().Split().Select(long.Parse).ToArray();

    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, m) = (c[0], c[1]);
        var ng = ((decimal)Math.Sqrt(n) + 1000) * 100_000_000;
        var n2 = (decimal)n;
        for (var i = 0; i < 16; ++i) n2 *= 10;
        var ok = decimal.Zero;
        while (ng - ok > 1)
        {
            var mid = decimal.Floor((ng + ok) / 2);
            if (mid * mid <= n2) ok = mid;
            else ng = mid;
        }
        var rn = ok;
        ok = decimal.Ceiling((decimal)m * 5 / 2);
        ng = 0;
        while (ok - ng > 1)
        {
            var mid = decimal.Floor((ng + ok) / 2);
            if (mid * rn - mid * 100_000_000 >= m * 100_000_000) ok = mid;
            else ng = mid;
        }
        WriteLine(decimal.Floor(ok * rn / 100_000_000) - decimal.Floor((ok * rn - ok * 100_000_000 - m * 100_000_000) / 100_000_000) - 1);
    }
}