Problem:
Score : 100 points

Problem Statement

There are S sheep and W wolves.

If the number of wolves is greater than or equal to that of sheep, the wolves will attack the sheep.

If the wolves will attack the sheep, print unsafe; otherwise, print safe.

Constraints

1 \leq S \leq 100

1 \leq W \leq 100

Input

Input is given from Standard Input in the following format:

S W

Output

If the wolves will attack the sheep, print unsafe; otherwise, print safe.

Sample Input 1

4 5

Sample Output 1

unsafe

There are four sheep and five wolves. The number of wolves is not less than that of sheep, so they will attack them.

Sample Input 2

100 2

Sample Output 2

safe

Many a sheep drive away two wolves.

Sample Input 3

10 10

Sample Output 3

unsafe

Solution in C# (.NET Core 3.1.201) (judge verdict: Wrong Answer)

using System;
using static System.Console;
using static System.Math;
using System.Numerics;
using System.Collections.Generic;
using System.Linq;


public class Program
{
    public static void Main(string[] args)
    {
        var s = myRead.readIntArray();
        var ans = (s[0] > 2 * s[1]) ? "safe" : "unsafe";
        WriteLine(ans);
    }
}
public static class myRead
{
    public static int readInt() { return int.Parse(ReadLine()); }
    public static long readLong() { return long.Parse(ReadLine()); }
    public static string reatStr() { return ReadLine(); }
    public static int[] readIntArray() { return ReadLine().Split(' ').Select(int.Parse).ToArray(); }
    public static long[] readLongArray() { return ReadLine().Split(' ').Select(long.Parse).ToArray(); }
    public static string[] readStrArray() { return ReadLine().Split(' '); }
}


public static class MyMath
{
    public static long Factorical(long n)
    { return n <= 1 ? 1L : n * Factorical(n - 1); }
    public static long Permutation(long n, long m)
    { return m == 0 ? 1L : (m == n) ? Permutation(n, m - 1) : n * Permutation(n - 1, m - 1); }
    public static long Combination(long n, long m)
    { return n - m > m ? Permutation(n, m) / Factorical(m) : Permutation(n, n - m) / Factorical(n - m); }
    public static long Gcd(long n, long m)
    { return n % m == 0 ? m : Gcd(m, n % m); }
    public static long Lcm(long n, long m)
    { return n * m / Gcd(n, m); }
    public static long Pow(long n, long m)
    { return m == 0 ? 1L : m == 1 ? n : n * Pow(n, m - 1); }
}