[백준] 2193번 : 이친수 - C#

https://www.acmicpc.net/problem/2193

using System;

class Program
{
    static void Main() {
        string s=Console.ReadLine();
        int n=int.Parse(s);
        long[] arr=new long[n+1];
        arr[1]=1;
        for(int i=2;i<=n;i++){
            arr[i]=arr[i-1]+arr[i-2];
        }
        Console.Write(arr[n]);
    }
}