import java.util.*;
import java.io.*;

public class Main {
	static PrintWriter out;
	static StringBuilder sb;
	static int mod = 998244353;
	static long inf = (long) 1e18 + 1;
	static int[] col;
	static int n, m;
	static ArrayList<Integer>[] ad;
	static long[][][] memo;
	static HashSet<Integer> h;
	static int[] a;
	static Integer[][] g;

	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		out = new PrintWriter(System.out);
		if(sc.nextInt()>sc.nextInt())
			System.out.println("safe");
		else
			System.out.println("unsafe");
		out.flush();
	}

	static long modPow(long a, long e)

	{
		long res = 1;
		while (e > 0) {
			if ((e & 1) == 1)
				res = (res * a) % mod;
			a = (a * a) % mod;
			e >>= 1;
		}
		return res;
	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream system) {
			br = new BufferedReader(new InputStreamReader(system));
		}

		public Scanner(String file) throws Exception {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public char nextChar() throws IOException {
			return next().charAt(0);
		}

		public Long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public int[] nextArrInt(int n) throws IOException {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

		public long[] nextArrLong(int n) throws IOException {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextLong();
			return a;
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

		public void waitForInput() throws InterruptedException {
			Thread.sleep(3000);
		}
	}
} import java.util.*; util.* java import java.io.*; io.* java public class Main {
	static PrintWriter out;
	static StringBuilder sb;
	static int mod = 998244353;
	static long inf = (long) 1e18 + 1;
	static int[] col;
	static int n, m;
	static ArrayList<Integer>[] ad;
	static long[][][] memo;
	static HashSet<Integer> h;
	static int[] a;
	static Integer[][] g;

	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		out = new PrintWriter(System.out);
		if(sc.nextInt()>sc.nextInt())
			System.out.println("safe");
		else
			System.out.println("unsafe");
		out.flush();
	}

	static long modPow(long a, long e)

	{
		long res = 1;
		while (e > 0) {
			if ((e & 1) == 1)
				res = (res * a) % mod;
			a = (a * a) % mod;
			e >>= 1;
		}
		return res;
	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream system) {
			br = new BufferedReader(new InputStreamReader(system));
		}

		public Scanner(String file) throws Exception {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public char nextChar() throws IOException {
			return next().charAt(0);
		}

		public Long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public int[] nextArrInt(int n) throws IOException {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

		public long[] nextArrLong(int n) throws IOException {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextLong();
			return a;
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

		public void waitForInput() throws InterruptedException {
			Thread.sleep(3000);
		}
	}
} Main static PrintWriter out; out static StringBuilder sb; sb static int mod = 998244353; mod 998244353 static long inf = (long) 1e18 + 1; inf (long) 1e18 + 1 (long) 1e18 1 static int[] col; col static int n n m; m static ArrayList<Integer>[] ad; ad static long[][][] memo; memo static HashSet<Integer> h; h static int[] a; a static Integer[][] g; g public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		out = new PrintWriter(System.out);
		if(sc.nextInt()>sc.nextInt())
			System.out.println("safe");
		else
			System.out.println("unsafe");
		out.flush();
	} main {
		Scanner sc = new Scanner(System.in);
		out = new PrintWriter(System.out);
		if(sc.nextInt()>sc.nextInt())
			System.out.println("safe");
		else
			System.out.println("unsafe");
		out.flush();
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) out = new PrintWriter(System.out) out new PrintWriter(System.out) if(sc.nextInt()>sc.nextInt())
			System.out.println("safe");
		else
			System.out.println("unsafe"); sc.nextInt()>sc.nextInt() sc.nextInt() sc.nextInt sc sc.nextInt() sc.nextInt sc System.out.println("safe") System.out.println System.out System System.out "safe" System.out.println("unsafe") System.out.println System.out System System.out "unsafe" out.flush() out.flush out String[] args args static long modPow(long a, long e)

	{
		long res = 1;
		while (e > 0) {
			if ((e & 1) == 1)
				res = (res * a) % mod;
			a = (a * a) % mod;
			e >>= 1;
		}
		return res;
	} modPow {
		long res = 1;
		while (e > 0) {
			if ((e & 1) == 1)
				res = (res * a) % mod;
			a = (a * a) % mod;
			e >>= 1;
		}
		return res;
	} long res = 1; res 1 while (e > 0) {
			if ((e & 1) == 1)
				res = (res * a) % mod;
			a = (a * a) % mod;
			e >>= 1;
		} e > 0 e 0 {
			if ((e & 1) == 1)
				res = (res * a) % mod;
			a = (a * a) % mod;
			e >>= 1;
		} if ((e & 1) == 1)
				res = (res * a) % mod; (e & 1) == 1 (e & 1) e 1 1 res = (res * a) % mod res (res * a) % mod (res * a) res a mod a = (a * a) % mod a (a * a) % mod (a * a) a a mod e >>= 1 e 1 return res; res long a a long e e static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream system) {
			br = new BufferedReader(new InputStreamReader(system));
		}

		public Scanner(String file) throws Exception {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public char nextChar() throws IOException {
			return next().charAt(0);
		}

		public Long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public int[] nextArrInt(int n) throws IOException {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

		public long[] nextArrLong(int n) throws IOException {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextLong();
			return a;
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

		public void waitForInput() throws InterruptedException {
			Thread.sleep(3000);
		}
	} Scanner StringTokenizer st; st BufferedReader br; br public Scanner(InputStream system) {
			br = new BufferedReader(new InputStreamReader(system));
		} Scanner {
			br = new BufferedReader(new InputStreamReader(system));
		} br = new BufferedReader(new InputStreamReader(system)) br new BufferedReader(new InputStreamReader(system)) InputStream system system public Scanner(String file) throws Exception {
			br = new BufferedReader(new FileReader(file));
		} Scanner {
			br = new BufferedReader(new FileReader(file));
		} br = new BufferedReader(new FileReader(file)) br new BufferedReader(new FileReader(file)) String file file public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		} next {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		} while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine()); st == null || !st.hasMoreTokens() st == null st null !st.hasMoreTokens() st.hasMoreTokens() st.hasMoreTokens st st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st public String nextLine() throws IOException {
			return br.readLine();
		} nextLine {
			return br.readLine();
		} return br.readLine(); br.readLine() br.readLine br public int nextInt() throws IOException {
			return Integer.parseInt(next());
		} nextInt {
			return Integer.parseInt(next());
		} return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		} nextDouble {
			return Double.parseDouble(next());
		} return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next public char nextChar() throws IOException {
			return next().charAt(0);
		} nextChar {
			return next().charAt(0);
		} return next().charAt(0); next().charAt(0) next().charAt next() next 0 public Long nextLong() throws IOException {
			return Long.parseLong(next());
		} nextLong {
			return Long.parseLong(next());
		} return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public int[] nextArrInt(int n) throws IOException {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		} nextArrInt {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		} int[] a = new int[n]; a new int[n] n for (int i = 0; i < n; i++)
				a[i] = nextInt(); int i = 0; int i = 0; i 0 i < n i n i++ i++ i a[i] = nextInt(); a[i] = nextInt() a[i] a i nextInt() nextInt return a; a int n n public long[] nextArrLong(int n) throws IOException {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextLong();
			return a;
		} nextArrLong {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextLong();
			return a;
		} long[] a = new long[n]; a new long[n] n for (int i = 0; i < n; i++)
				a[i] = nextLong(); int i = 0; int i = 0; i 0 i < n i n i++ i++ i a[i] = nextLong(); a[i] = nextLong() a[i] a i nextLong() nextLong return a; a int n n public boolean ready() throws IOException {
			return br.ready();
		} ready {
			return br.ready();
		} return br.ready(); br.ready() br.ready br public void waitForInput() throws InterruptedException {
			Thread.sleep(3000);
		} waitForInput {
			Thread.sleep(3000);
		} Thread.sleep(3000) Thread.sleep Thread 3000 public class Main {
	static PrintWriter out;
	static StringBuilder sb;
	static int mod = 998244353;
	static long inf = (long) 1e18 + 1;
	static int[] col;
	static int n, m;
	static ArrayList<Integer>[] ad;
	static long[][][] memo;
	static HashSet<Integer> h;
	static int[] a;
	static Integer[][] g;

	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		out = new PrintWriter(System.out);
		if(sc.nextInt()>sc.nextInt())
			System.out.println("safe");
		else
			System.out.println("unsafe");
		out.flush();
	}

	static long modPow(long a, long e)

	{
		long res = 1;
		while (e > 0) {
			if ((e & 1) == 1)
				res = (res * a) % mod;
			a = (a * a) % mod;
			e >>= 1;
		}
		return res;
	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream system) {
			br = new BufferedReader(new InputStreamReader(system));
		}

		public Scanner(String file) throws Exception {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public char nextChar() throws IOException {
			return next().charAt(0);
		}

		public Long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public int[] nextArrInt(int n) throws IOException {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

		public long[] nextArrLong(int n) throws IOException {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextLong();
			return a;
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

		public void waitForInput() throws InterruptedException {
			Thread.sleep(3000);
		}
	}
} public class Main {
	static PrintWriter out;
	static StringBuilder sb;
	static int mod = 998244353;
	static long inf = (long) 1e18 + 1;
	static int[] col;
	static int n, m;
	static ArrayList<Integer>[] ad;
	static long[][][] memo;
	static HashSet<Integer> h;
	static int[] a;
	static Integer[][] g;

	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		out = new PrintWriter(System.out);
		if(sc.nextInt()>sc.nextInt())
			System.out.println("safe");
		else
			System.out.println("unsafe");
		out.flush();
	}

	static long modPow(long a, long e)

	{
		long res = 1;
		while (e > 0) {
			if ((e & 1) == 1)
				res = (res * a) % mod;
			a = (a * a) % mod;
			e >>= 1;
		}
		return res;
	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream system) {
			br = new BufferedReader(new InputStreamReader(system));
		}

		public Scanner(String file) throws Exception {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public char nextChar() throws IOException {
			return next().charAt(0);
		}

		public Long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public int[] nextArrInt(int n) throws IOException {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

		public long[] nextArrLong(int n) throws IOException {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextLong();
			return a;
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

		public void waitForInput() throws InterruptedException {
			Thread.sleep(3000);
		}
	}
} Main
import java.util.*;
import java.io.*;

public class Main {
	static PrintWriter out;
	static StringBuilder sb;
	static int mod = 998244353;
	static long inf = (long) 1e18 + 1;
	static int[] col;
	static int n, m;
	static ArrayList<Integer>[] ad;
	static long[][][] memo;
	static HashSet<Integer> h;
	static int[] a;
	static Integer[][] g;

	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		out = new PrintWriter(System.out);
		if(sc.nextInt()>sc.nextInt())
			System.out.println("safe");
		else
			System.out.println("unsafe");
		out.flush();
	}

	static long modPow(long a, long e)

	{
		long res = 1;
		while (e > 0) {
			if ((e & 1) == 1)
				res = (res * a) % mod;
			a = (a * a) % mod;
			e >>= 1;
		}
		return res;
	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream system) {
			br = new BufferedReader(new InputStreamReader(system));
		}

		public Scanner(String file) throws Exception {
			br = new BufferedReader(new FileReader(file));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		public char nextChar() throws IOException {
			return next().charAt(0);
		}

		public Long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public int[] nextArrInt(int n) throws IOException {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

		public long[] nextArrLong(int n) throws IOException {
			long[] a = new long[n];
			for (int i = 0; i < n; i++)
				a[i] = nextLong();
			return a;
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

		public void waitForInput() throws InterruptedException {
			Thread.sleep(3000);
		}
	}
}