Problem:
Score : 200 points

Problem Statement

It is November 18 now in Japan. By the way, 11 and 18 are adjacent Lucas numbers.

You are given an integer N. Find the N-th Lucas number.

Here, the i-th Lucas number L_i is defined as follows:

L_0=2

L_1=1

L_i=L_{i-1}+L_{i-2} (i≥2)

Constraints

1≤N≤86

It is guaranteed that the answer is less than 10^{18}.

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the N-th Lucas number.

Sample Input 1

5

Sample Output 1

11

L_0=2

L_1=1

L_2=L_0+L_1=3

L_3=L_1+L_2=4

L_4=L_2+L_3=7

L_5=L_3+L_4=11

Thus, the 5-th Lucas number is 11.

Sample Input 2

86

Sample Output 2

939587134549734843

Solution in Kotlin (1.0.0) (judge verdict: Wrong Answer)

import java.util.*

/**
 * Created by Shadab on 26-Nov-17.
 */
fun main(args: Array<String>){

    //Generating Lucas numbers array.
    var lucas: Array<Long?> = kotlin.arrayOfNulls<Long>(86)

    lucas.set(0, 2)
    lucas.set(1, 1)

    for (i in 2..85) {
        var total = lucas.get(i - 1) as Long + lucas.get(i - 2) as Long
        lucas.set(i, total)
    }

    //taking user input for Lucas number position
    var sc =  Scanner(System.`in`)

    while(sc.hasNext()) {

        var n = sc.nextInt();
        println(lucas.get(n-1))
    }

}