import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedList;
import java.util.Scanner;

class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int S = sc.nextInt();
    int W = sc.nextInt();
    if (W >= S) {
      System.out.println("unsafe");
    } else {
      System.out.println("safe");
    }
  }
} import java.util.Arrays; Arrays java.util import java.util.Collections; Collections java.util import java.util.LinkedList; LinkedList java.util import java.util.Scanner; Scanner java.util class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int S = sc.nextInt();
    int W = sc.nextInt();
    if (W >= S) {
      System.out.println("unsafe");
    } else {
      System.out.println("safe");
    }
  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int S = sc.nextInt();
    int W = sc.nextInt();
    if (W >= S) {
      System.out.println("unsafe");
    } else {
      System.out.println("safe");
    }
  } main {
    Scanner sc = new Scanner(System.in);
    int S = sc.nextInt();
    int W = sc.nextInt();
    if (W >= S) {
      System.out.println("unsafe");
    } else {
      System.out.println("safe");
    }
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int S = sc.nextInt(); S sc.nextInt() sc.nextInt sc int W = sc.nextInt(); W sc.nextInt() sc.nextInt sc if (W >= S) {
      System.out.println("unsafe");
    } else {
      System.out.println("safe");
    } W >= S W S {
      System.out.println("unsafe");
    } System.out.println("unsafe") System.out.println System.out System System.out "unsafe" {
      System.out.println("safe");
    } System.out.println("safe") System.out.println System.out System System.out "safe" String[] args args
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedList;
import java.util.Scanner;

class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int S = sc.nextInt();
    int W = sc.nextInt();
    if (W >= S) {
      System.out.println("unsafe");
    } else {
      System.out.println("safe");
    }
  }
}