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

class MainClass
{

    public static void Main(string[] args)
    {
        var _ = LnInts();
        var S = _[0];var W = _[1];
        var re = W >= S ? "unsafe" : "safe";
        Console.WriteLine(re);
    }
   

public static long Gcd(long a, long b) { if (a > b) { var r = a % b; if (r == 0) return b; else return Gcd(b, r); } else { var r = b % a; if (r == 0) return a; else return Gcd(a, r); } }
    public static int Gcd(int a, int b) { if (a > b) { var r = a % b; if (r == 0) return b; else return Gcd(b, r); } else { var r = b % a; if (r == 0) return a; else return Gcd(a, r); } }
    public static int[] LnInts() { var vs = Console.ReadLine().Trim().Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries); var ins = new int[vs.Length]; for (int i = 0; i < vs.Length; i++) ins[i] = int.Parse(vs[i]); return ins; }
    public static int LnInt() { var vs = Console.ReadLine().Trim(); return int.Parse(vs); }
    public static long[] LnLngs() { var vs = Console.ReadLine().Trim().Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries); var ins = new long[vs.Length]; for (int i = 0; i < vs.Length; i++) ins[i] = long.Parse(vs[i]); return ins; }
    public static long LnLng() { var vs = Console.ReadLine().Trim(); return long.Parse(vs); }
    public static string[] LnStrs() { var vs = Console.ReadLine().Trim().Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries); return vs; }
    public static string LnStr() { var vs = Console.ReadLine().Trim(); return vs; }
}
