using System;

namespace SerieDeux
{
	class MainClass
	{
		public static void Main (string[] args)
		{
			double precision = 1E-15;
			double somme = 0;
			double terme = 1;
			double x;
			int i = 0;
			Console.Write ("Saisissez x : ");
			x = double.Parse (Console.ReadLine());
			while (Math.Abs(terme) > precision)
			{
				somme += terme;
				i++;
				terme *= x/i;
			}
			Console.WriteLine("exp(" + x + ") = " + somme);
		}
	}
}