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;

namespace _20200426_ABC164A
{
    class Program
    {
        static void Main(string[] args)
        {
            var input = ReadStringList(1);

            string[] sp = input[0].Split(' ');
            int S = int.Parse(sp[0]);
            int W = int.Parse(sp[1]);

            string output = "unsafe";
            if (S > W)
            {
                output = "safe";
            }

            Console.WriteLine(output);
        }

        private static List<string> ReadStringList(int numberOfLines)
        {
            var stringList = new List<string>();

            for (int lineIndex = 0; lineIndex < numberOfLines; lineIndex++)
            {
                stringList.Add(Console.ReadLine().Trim());
            }

            return stringList;
        }
    }
}