import java.util.*;
import java.io.*;
class Main {
    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st= new StringTokenizer(br.readLine());
        int S = Integer.parseInt(st.nextToken());
        int W = Integer.parseInt(st.nextToken());
        String ans = W>=S ? "unsafe":"safe";
        System.out.println(ans);
    }
} import java.util.*; util.* java import java.io.*; io.* java class Main {
    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st= new StringTokenizer(br.readLine());
        int S = Integer.parseInt(st.nextToken());
        int W = Integer.parseInt(st.nextToken());
        String ans = W>=S ? "unsafe":"safe";
        System.out.println(ans);
    }
} Main public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st= new StringTokenizer(br.readLine());
        int S = Integer.parseInt(st.nextToken());
        int W = Integer.parseInt(st.nextToken());
        String ans = W>=S ? "unsafe":"safe";
        System.out.println(ans);
    } main {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st= new StringTokenizer(br.readLine());
        int S = Integer.parseInt(st.nextToken());
        int W = Integer.parseInt(st.nextToken());
        String ans = W>=S ? "unsafe":"safe";
        System.out.println(ans);
    } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) StringTokenizer st= new StringTokenizer(br.readLine()); st new StringTokenizer(br.readLine()) int S = Integer.parseInt(st.nextToken()); S Integer.parseInt(st.nextToken()) Integer.parseInt Integer st.nextToken() st.nextToken st int W = Integer.parseInt(st.nextToken()); W Integer.parseInt(st.nextToken()) Integer.parseInt Integer st.nextToken() st.nextToken st String ans = W>=S ? "unsafe":"safe"; ans W>=S ? "unsafe":"safe" W>=S W S "unsafe" "safe" System.out.println(ans) System.out.println System.out System System.out ans String[] args args
import java.util.*;
import java.io.*;
class Main {
    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st= new StringTokenizer(br.readLine());
        int S = Integer.parseInt(st.nextToken());
        int W = Integer.parseInt(st.nextToken());
        String ans = W>=S ? "unsafe":"safe";
        System.out.println(ans);
    }
}