import java.util.*;
import java.util.ArrayDeque;
import java.util.Queue;
import java.math.RoundingMode;
import java.math.BigDecimal;



public class Main{
	 public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
	   	int s = sc.nextInt();
	   	int w = sc.nextInt();
	   	if(s<=w) {
	   		System.out.println("unsafe");
	   	}
	   	else {
	   		System.out.println("safe");
	   	}
	 }
} import java.util.*; util.* java import java.util.ArrayDeque; ArrayDeque java.util import java.util.Queue; Queue java.util import java.math.RoundingMode; RoundingMode java.math import java.math.BigDecimal; BigDecimal java.math public class Main{
	 public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
	   	int s = sc.nextInt();
	   	int w = sc.nextInt();
	   	if(s<=w) {
	   		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(s<=w) {
	   		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(s<=w) {
	   		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(s<=w) {
	   		System.out.println("unsafe");
	   	}
	   	else {
	   		System.out.println("safe");
	   	} s<=w s w {
	   		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 public class Main{
	 public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
	   	int s = sc.nextInt();
	   	int w = sc.nextInt();
	   	if(s<=w) {
	   		System.out.println("unsafe");
	   	}
	   	else {
	   		System.out.println("safe");
	   	}
	 }
} public class Main{
	 public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
	   	int s = sc.nextInt();
	   	int w = sc.nextInt();
	   	if(s<=w) {
	   		System.out.println("unsafe");
	   	}
	   	else {
	   		System.out.println("safe");
	   	}
	 }
} Main
import java.util.*;
import java.util.ArrayDeque;
import java.util.Queue;
import java.math.RoundingMode;
import java.math.BigDecimal;



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