Tiling With 2 * 1 Tiles

 1. You are given a number n representing the length of a floor space which is 2m wide. It's a 2 * n board.

2. You've an infinite supply of 2 * 1 tiles.

3. You are required to calculate and print the number of ways floor can be tiled using tiles.

Input Format

A number n

Output Format

A number representing the number of ways in which the number of ways floor can be tiled using tiles.

Constraints

1 <= n <= 100

Sample Input

8

Sample Output

34

Solution:

import java.io.*;

import java.util.*;

public class Main {

    public static void main(String[] args) throws Exception {

        // input

        Scanner sc = new  Scanner(System.in);

        int n = sc.nextInt();

        int prev = 1, next = 1, sum = 0;

        for(int i=2;i<=n;i++){

            sum = prev + next;

            prev =next;

            next = sum;

        }

        System.out.println(next);

    }

}