using System; using static System.Console; using System.Linq; using System.Collections.Generic; class Program { static long NN => long.Parse(ReadLine()); public static void Main() { Solve(); } static void Solve() { var n = NN; var sq = (long)Math.Sqrt(n); while ((sq + 1) * (sq + 1) <= n) ++sq; WriteLine(sq); } }