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: Accepted)

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

namespace Atcoder
{
	class Program
	{
		static void Main(string[] args)
		{


			//テンプレート
			//// 整数の入力
			//int a = int.Parse(Console.ReadLine());

			//// スペース区切りの整数の入力
			//string[] input = Console.ReadLine().Split(' ');
			//int b = int.Parse(input[0]);
			//int c = int.Parse(input[1]);

			//// 文字列の入力
			//string s = Console.ReadLine();

			////出力
			//Console.WriteLine(a + b + c + " " + s);

			//A

			string[] input = Console.ReadLine().Split(' ');
			int s = int.Parse(input[0]);
			int w = int.Parse(input[1]);

			if (s <= w)
			{
				Console.WriteLine("unsafe");
			}
			else
			{
				Console.WriteLine("safe");
			}

			Console.ReadLine();

		}
	}
}