using System;
public class Program
{
public static void Main()
int n = int.Parse(Console.ReadLine());
int num1 = 1;
int num2 = 1;
for (int i = 0; i < n; i++)
int numNext = num1 + num2;
num1 = num2;
num2 = numNext;
}
Console.WriteLine(num1);