import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
	private static void solveTC(int __) {
		
		/* For Google */
//		ans.append("Case #").append(__).append(": ");

//		code start

		int s=scn.nextInt(),w=scn.nextInt();
		if (w>=s){
			print("unsafe");
		}else {
			print("safe");
		}

//		code end

		ans.append("\n");
	}

	static void print(Object obj) {
		ans.append(obj.toString());
	}

	public static void main(String[] args) {
		
		scn = new Scanner();
//		int t = scn.nextInt();
		int t = 1;
		for (int i = 1; i <= t; i++) {
			ans = new StringBuilder();
			solveTC(i);
			System.out.print(ans);
		}
		
	}
	
	static Scanner scn;
	static StringBuilder ans;
	
	//Fast Scanner
	static class Scanner {
		BufferedReader br;
		StringTokenizer st;
		
		public Scanner() {
			br = new BufferedReader(new
					InputStreamReader(System.in));
		}
		
		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		
		long nextLong() {
			return Long.parseLong(next());
		}
		
		double nextDouble() {
			return Double.parseDouble(next());
		}
		
		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
		
		int[] nextIntArray(int n) {
			int[] array = new int[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		}
		
		Integer[] nextIntegerArray(int n) {
			Integer[] array = new Integer[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		}
		
		long[] nextLongArray(int n) {
			long[] array = new long[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextLong();
			}
			return array;
		}
		
		String[] nextStringArray() {
			return nextLine().split(" ");
		}
		
		String[] nextStringArray(int n) {
			String[] array = new String[n];
			for (int i = 0; i < n; i++) {
				array[i] = next();
			}
			return array;
		}
	}
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.StringTokenizer; StringTokenizer java.util public class Main {
	private static void solveTC(int __) {
		
		/* For Google */
//		ans.append("Case #").append(__).append(": ");

//		code start

		int s=scn.nextInt(),w=scn.nextInt();
		if (w>=s){
			print("unsafe");
		}else {
			print("safe");
		}

//		code end

		ans.append("\n");
	}

	static void print(Object obj) {
		ans.append(obj.toString());
	}

	public static void main(String[] args) {
		
		scn = new Scanner();
//		int t = scn.nextInt();
		int t = 1;
		for (int i = 1; i <= t; i++) {
			ans = new StringBuilder();
			solveTC(i);
			System.out.print(ans);
		}
		
	}
	
	static Scanner scn;
	static StringBuilder ans;
	
	//Fast Scanner
	static class Scanner {
		BufferedReader br;
		StringTokenizer st;
		
		public Scanner() {
			br = new BufferedReader(new
					InputStreamReader(System.in));
		}
		
		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		
		long nextLong() {
			return Long.parseLong(next());
		}
		
		double nextDouble() {
			return Double.parseDouble(next());
		}
		
		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
		
		int[] nextIntArray(int n) {
			int[] array = new int[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		}
		
		Integer[] nextIntegerArray(int n) {
			Integer[] array = new Integer[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		}
		
		long[] nextLongArray(int n) {
			long[] array = new long[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextLong();
			}
			return array;
		}
		
		String[] nextStringArray() {
			return nextLine().split(" ");
		}
		
		String[] nextStringArray(int n) {
			String[] array = new String[n];
			for (int i = 0; i < n; i++) {
				array[i] = next();
			}
			return array;
		}
	}
} Main static Scanner scn; scn static StringBuilder ans; ans private static void solveTC(int __) {
		
		/* For Google */
//		ans.append("Case #").append(__).append(": ");

//		code start

		int s=scn.nextInt(),w=scn.nextInt();
		if (w>=s){
			print("unsafe");
		}else {
			print("safe");
		}

//		code end

		ans.append("\n");
	} solveTC {
		
		/* For Google */
//		ans.append("Case #").append(__).append(": ");

//		code start

		int s=scn.nextInt(),w=scn.nextInt();
		if (w>=s){
			print("unsafe");
		}else {
			print("safe");
		}

//		code end

		ans.append("\n");
	} int s=scn.nextInt() s scn.nextInt() scn.nextInt scn w=scn.nextInt(); w scn.nextInt() scn.nextInt scn if (w>=s){
			print("unsafe");
		}else {
			print("safe");
		} w>=s w s {
			print("unsafe");
		} print("unsafe") print "unsafe" {
			print("safe");
		} print("safe") print "safe" ans.append("\n") ans.append ans "\n" int __ __ static void print(Object obj) {
		ans.append(obj.toString());
	} print {
		ans.append(obj.toString());
	} ans.append(obj.toString()) ans.append ans obj.toString() obj.toString obj Object obj obj public static void main(String[] args) {
		
		scn = new Scanner();
//		int t = scn.nextInt();
		int t = 1;
		for (int i = 1; i <= t; i++) {
			ans = new StringBuilder();
			solveTC(i);
			System.out.print(ans);
		}
		
	} main {
		
		scn = new Scanner();
//		int t = scn.nextInt();
		int t = 1;
		for (int i = 1; i <= t; i++) {
			ans = new StringBuilder();
			solveTC(i);
			System.out.print(ans);
		}
		
	} scn = new Scanner() scn new Scanner() int t = 1; t 1 for (int i = 1; i <= t; i++) {
			ans = new StringBuilder();
			solveTC(i);
			System.out.print(ans);
		} int i = 1; int i = 1; i 1 i <= t i t i++ i++ i {
			ans = new StringBuilder();
			solveTC(i);
			System.out.print(ans);
		} {
			ans = new StringBuilder();
			solveTC(i);
			System.out.print(ans);
		} ans = new StringBuilder() ans new StringBuilder() solveTC(i) solveTC i System.out.print(ans) System.out.print System.out System System.out ans String[] args args static class Scanner {
		BufferedReader br;
		StringTokenizer st;
		
		public Scanner() {
			br = new BufferedReader(new
					InputStreamReader(System.in));
		}
		
		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		
		long nextLong() {
			return Long.parseLong(next());
		}
		
		double nextDouble() {
			return Double.parseDouble(next());
		}
		
		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
		
		int[] nextIntArray(int n) {
			int[] array = new int[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		}
		
		Integer[] nextIntegerArray(int n) {
			Integer[] array = new Integer[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		}
		
		long[] nextLongArray(int n) {
			long[] array = new long[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextLong();
			}
			return array;
		}
		
		String[] nextStringArray() {
			return nextLine().split(" ");
		}
		
		String[] nextStringArray(int n) {
			String[] array = new String[n];
			for (int i = 0; i < n; i++) {
				array[i] = next();
			}
			return array;
		}
	} Scanner BufferedReader br; br StringTokenizer st; st public Scanner() {
			br = new BufferedReader(new
					InputStreamReader(System.in));
		} Scanner {
			br = new BufferedReader(new
					InputStreamReader(System.in));
		} br = new BufferedReader(new
					InputStreamReader(System.in)) br new BufferedReader(new
					InputStreamReader(System.in)) String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		} next {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		} while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			} st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			} try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				} catch (IOException e) {
					e.printStackTrace();
				} IOException e {
					e.printStackTrace();
				} e.printStackTrace() e.printStackTrace e {
					st = new StringTokenizer(br.readLine());
				} st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() {
			return Integer.parseInt(next());
		} nextInt {
			return Integer.parseInt(next());
		} return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() {
			return Long.parseLong(next());
		} nextLong {
			return Long.parseLong(next());
		} return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble() {
			return Double.parseDouble(next());
		} nextDouble {
			return Double.parseDouble(next());
		} return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		} nextLine {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		} String str = ""; str "" try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			} catch (IOException e) {
				e.printStackTrace();
			} IOException e {
				e.printStackTrace();
			} e.printStackTrace() e.printStackTrace e {
				str = br.readLine();
			} str = br.readLine() str br.readLine() br.readLine br return str; str int[] nextIntArray(int n) {
			int[] array = new int[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		} nextIntArray {
			int[] array = new int[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		} int[] array = new int[n]; array new int[n] n for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
				array[i] = nextInt();
			} {
				array[i] = nextInt();
			} array[i] = nextInt() array[i] array i nextInt() nextInt return array; array int n n Integer[] nextIntegerArray(int n) {
			Integer[] array = new Integer[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		} nextIntegerArray {
			Integer[] array = new Integer[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		} Integer[] array = new Integer[n]; array new Integer[n] n for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
				array[i] = nextInt();
			} {
				array[i] = nextInt();
			} array[i] = nextInt() array[i] array i nextInt() nextInt return array; array int n n long[] nextLongArray(int n) {
			long[] array = new long[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextLong();
			}
			return array;
		} nextLongArray {
			long[] array = new long[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextLong();
			}
			return array;
		} long[] array = new long[n]; array new long[n] n for (int i = 0; i < n; i++) {
				array[i] = nextLong();
			} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
				array[i] = nextLong();
			} {
				array[i] = nextLong();
			} array[i] = nextLong() array[i] array i nextLong() nextLong return array; array int n n String[] nextStringArray() {
			return nextLine().split(" ");
		} nextStringArray {
			return nextLine().split(" ");
		} return nextLine().split(" "); nextLine().split(" ") nextLine().split nextLine() nextLine " " String[] nextStringArray(int n) {
			String[] array = new String[n];
			for (int i = 0; i < n; i++) {
				array[i] = next();
			}
			return array;
		} nextStringArray {
			String[] array = new String[n];
			for (int i = 0; i < n; i++) {
				array[i] = next();
			}
			return array;
		} String[] array = new String[n]; array new String[n] n for (int i = 0; i < n; i++) {
				array[i] = next();
			} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
				array[i] = next();
			} {
				array[i] = next();
			} array[i] = next() array[i] array i next() next return array; array int n n public class Main {
	private static void solveTC(int __) {
		
		/* For Google */
//		ans.append("Case #").append(__).append(": ");

//		code start

		int s=scn.nextInt(),w=scn.nextInt();
		if (w>=s){
			print("unsafe");
		}else {
			print("safe");
		}

//		code end

		ans.append("\n");
	}

	static void print(Object obj) {
		ans.append(obj.toString());
	}

	public static void main(String[] args) {
		
		scn = new Scanner();
//		int t = scn.nextInt();
		int t = 1;
		for (int i = 1; i <= t; i++) {
			ans = new StringBuilder();
			solveTC(i);
			System.out.print(ans);
		}
		
	}
	
	static Scanner scn;
	static StringBuilder ans;
	
	//Fast Scanner
	static class Scanner {
		BufferedReader br;
		StringTokenizer st;
		
		public Scanner() {
			br = new BufferedReader(new
					InputStreamReader(System.in));
		}
		
		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		
		long nextLong() {
			return Long.parseLong(next());
		}
		
		double nextDouble() {
			return Double.parseDouble(next());
		}
		
		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
		
		int[] nextIntArray(int n) {
			int[] array = new int[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		}
		
		Integer[] nextIntegerArray(int n) {
			Integer[] array = new Integer[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		}
		
		long[] nextLongArray(int n) {
			long[] array = new long[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextLong();
			}
			return array;
		}
		
		String[] nextStringArray() {
			return nextLine().split(" ");
		}
		
		String[] nextStringArray(int n) {
			String[] array = new String[n];
			for (int i = 0; i < n; i++) {
				array[i] = next();
			}
			return array;
		}
	}
} public class Main {
	private static void solveTC(int __) {
		
		/* For Google */
//		ans.append("Case #").append(__).append(": ");

//		code start

		int s=scn.nextInt(),w=scn.nextInt();
		if (w>=s){
			print("unsafe");
		}else {
			print("safe");
		}

//		code end

		ans.append("\n");
	}

	static void print(Object obj) {
		ans.append(obj.toString());
	}

	public static void main(String[] args) {
		
		scn = new Scanner();
//		int t = scn.nextInt();
		int t = 1;
		for (int i = 1; i <= t; i++) {
			ans = new StringBuilder();
			solveTC(i);
			System.out.print(ans);
		}
		
	}
	
	static Scanner scn;
	static StringBuilder ans;
	
	//Fast Scanner
	static class Scanner {
		BufferedReader br;
		StringTokenizer st;
		
		public Scanner() {
			br = new BufferedReader(new
					InputStreamReader(System.in));
		}
		
		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		
		long nextLong() {
			return Long.parseLong(next());
		}
		
		double nextDouble() {
			return Double.parseDouble(next());
		}
		
		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
		
		int[] nextIntArray(int n) {
			int[] array = new int[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		}
		
		Integer[] nextIntegerArray(int n) {
			Integer[] array = new Integer[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		}
		
		long[] nextLongArray(int n) {
			long[] array = new long[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextLong();
			}
			return array;
		}
		
		String[] nextStringArray() {
			return nextLine().split(" ");
		}
		
		String[] nextStringArray(int n) {
			String[] array = new String[n];
			for (int i = 0; i < n; i++) {
				array[i] = next();
			}
			return array;
		}
	}
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
	private static void solveTC(int __) {
		
		/* For Google */
//		ans.append("Case #").append(__).append(": ");

//		code start

		int s=scn.nextInt(),w=scn.nextInt();
		if (w>=s){
			print("unsafe");
		}else {
			print("safe");
		}

//		code end

		ans.append("\n");
	}

	static void print(Object obj) {
		ans.append(obj.toString());
	}

	public static void main(String[] args) {
		
		scn = new Scanner();
//		int t = scn.nextInt();
		int t = 1;
		for (int i = 1; i <= t; i++) {
			ans = new StringBuilder();
			solveTC(i);
			System.out.print(ans);
		}
		
	}
	
	static Scanner scn;
	static StringBuilder ans;
	
	//Fast Scanner
	static class Scanner {
		BufferedReader br;
		StringTokenizer st;
		
		public Scanner() {
			br = new BufferedReader(new
					InputStreamReader(System.in));
		}
		
		String next() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		
		long nextLong() {
			return Long.parseLong(next());
		}
		
		double nextDouble() {
			return Double.parseDouble(next());
		}
		
		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				e.printStackTrace();
			}
			return str;
		}
		
		int[] nextIntArray(int n) {
			int[] array = new int[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		}
		
		Integer[] nextIntegerArray(int n) {
			Integer[] array = new Integer[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextInt();
			}
			return array;
		}
		
		long[] nextLongArray(int n) {
			long[] array = new long[n];
			for (int i = 0; i < n; i++) {
				array[i] = nextLong();
			}
			return array;
		}
		
		String[] nextStringArray() {
			return nextLine().split(" ");
		}
		
		String[] nextStringArray(int n) {
			String[] array = new String[n];
			for (int i = 0; i < n; i++) {
				array[i] = next();
			}
			return array;
		}
	}
}