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# (Mono-mcs 6.8.0.105) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;

namespace a
{
    class Program
    {
        static void Main(string[] args)
        {
            var vals = IOUtils.ReadInts();
            var s = vals[0];
            var w = vals[1];

            Console.WriteLine(s <= w ? "unsafe" : "safe");


        }
    }

    static class IOUtils
    {
        public static int ReadInt()
        {
            return int.Parse(Console.ReadLine());
        }
        public static long ReadLong()
        {
            return long.Parse(Console.ReadLine());
        }
        public static ulong ReadUlong()
        {
            return ulong.Parse(Console.ReadLine());
        }
        public static int[] ReadInts()
        {
            return Console.ReadLine().Split(' ').Select(v => int.Parse(v)).ToArray();
        }
        public static long[] ReadLongs()
        {
            return Console.ReadLine().Split(' ').Select(v => long.Parse(v)).ToArray();
        }

        public static void WriteNums(params int[] nums)
        {
            Console.WriteLine(string.Join(" ", nums));
        }
    }
}