[백준] 2193번 이친수 문제! (silver 3

import java.io.*;
public class Main{
    public static void main(String[] args) throws IOException {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(System.out));
        long[] num=new long[91];
        num[1]=1;
        num[2]=1;
        for(int i=3; i<num.length; i++){
            num[i]=num[i-1]+num[i-2];
        }

        int n=Integer.parseInt(br.readLine());
        bw.write(num[n]+"");
        bw.flush();
     

    }
}