import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
  public static void main(final String[] args) throws Exception {
    try (BufferedReader r = new BufferedReader(new InputStreamReader(System.in))) {
      String s = r.readLine();
      String[] a = s.split(" ");
      int sheeps = Integer.parseInt(a[0]);
      int wolves = Integer.parseInt(a[1]);
      if (wolves >= sheeps) {
        System.out.println("unsafe");
      } else {
        System.out.println("safe");
      }
    }
  }
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {
  public static void main(final String[] args) throws Exception {
    try (BufferedReader r = new BufferedReader(new InputStreamReader(System.in))) {
      String s = r.readLine();
      String[] a = s.split(" ");
      int sheeps = Integer.parseInt(a[0]);
      int wolves = Integer.parseInt(a[1]);
      if (wolves >= sheeps) {
        System.out.println("unsafe");
      } else {
        System.out.println("safe");
      }
    }
  }
} Main public static void main(final String[] args) throws Exception {
    try (BufferedReader r = new BufferedReader(new InputStreamReader(System.in))) {
      String s = r.readLine();
      String[] a = s.split(" ");
      int sheeps = Integer.parseInt(a[0]);
      int wolves = Integer.parseInt(a[1]);
      if (wolves >= sheeps) {
        System.out.println("unsafe");
      } else {
        System.out.println("safe");
      }
    }
  } main {
    try (BufferedReader r = new BufferedReader(new InputStreamReader(System.in))) {
      String s = r.readLine();
      String[] a = s.split(" ");
      int sheeps = Integer.parseInt(a[0]);
      int wolves = Integer.parseInt(a[1]);
      if (wolves >= sheeps) {
        System.out.println("unsafe");
      } else {
        System.out.println("safe");
      }
    }
  } try (BufferedReader r = new BufferedReader(new InputStreamReader(System.in))) {
      String s = r.readLine();
      String[] a = s.split(" ");
      int sheeps = Integer.parseInt(a[0]);
      int wolves = Integer.parseInt(a[1]);
      if (wolves >= sheeps) {
        System.out.println("unsafe");
      } else {
        System.out.println("safe");
      }
    } {
      String s = r.readLine();
      String[] a = s.split(" ");
      int sheeps = Integer.parseInt(a[0]);
      int wolves = Integer.parseInt(a[1]);
      if (wolves >= sheeps) {
        System.out.println("unsafe");
      } else {
        System.out.println("safe");
      }
    } BufferedReader r = new BufferedReader(new InputStreamReader(System.in)) BufferedReader r = new BufferedReader(new InputStreamReader(System.in)) new BufferedReader(new InputStreamReader(System.in)) String s = r.readLine(); s r.readLine() r.readLine r String[] a = s.split(" "); a s.split(" ") s.split s " " int sheeps = Integer.parseInt(a[0]); sheeps Integer.parseInt(a[0]) Integer.parseInt Integer a[0] a 0 int wolves = Integer.parseInt(a[1]); wolves Integer.parseInt(a[1]) Integer.parseInt Integer a[1] a 1 if (wolves >= sheeps) {
        System.out.println("unsafe");
      } else {
        System.out.println("safe");
      } wolves >= sheeps wolves sheeps {
        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" final String[] args args public class Main {
  public static void main(final String[] args) throws Exception {
    try (BufferedReader r = new BufferedReader(new InputStreamReader(System.in))) {
      String s = r.readLine();
      String[] a = s.split(" ");
      int sheeps = Integer.parseInt(a[0]);
      int wolves = Integer.parseInt(a[1]);
      if (wolves >= sheeps) {
        System.out.println("unsafe");
      } else {
        System.out.println("safe");
      }
    }
  }
} public class Main {
  public static void main(final String[] args) throws Exception {
    try (BufferedReader r = new BufferedReader(new InputStreamReader(System.in))) {
      String s = r.readLine();
      String[] a = s.split(" ");
      int sheeps = Integer.parseInt(a[0]);
      int wolves = Integer.parseInt(a[1]);
      if (wolves >= sheeps) {
        System.out.println("unsafe");
      } else {
        System.out.println("safe");
      }
    }
  }
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
  public static void main(final String[] args) throws Exception {
    try (BufferedReader r = new BufferedReader(new InputStreamReader(System.in))) {
      String s = r.readLine();
      String[] a = s.split(" ");
      int sheeps = Integer.parseInt(a[0]);
      int wolves = Integer.parseInt(a[1]);
      if (wolves >= sheeps) {
        System.out.println("unsafe");
      } else {
        System.out.println("safe");
      }
    }
  }
}