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

namespace AtCoder
{
	class Program
	{
		static void Main(string[] args)
		{
			var firstLine = Console.ReadLine().Split(' ').Select(value => long.Parse(value)).ToArray();
			
			Console.WriteLine(firstLine[0] <= firstLine[1] ? "unsafe" : "safe");
		}
	}
}
