2193

Main.java

import java.util.*;
import java.math.*;

public class Main {
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        long[] d = new long[n+1];
        d[1] = 1;
        if (n >= 2) {
            d[2] = 1;
        }
        for (int i=3; i<=n; i++) {
            d[i] = d[i-1] + d[i-2];
        }
        System.out.println(d[n]);
    }
}