def issafe(S,W):

    if S > W:

        return "safe"

    return "unsafe"



S,W = list(map(int,input().split()))

print((issafe(S,W)))

def main():

  s,w = list(map(int,input().split()))

  if s>w:

    print("safe")

  else:

    print("unsafe")



main()

def issafe(S, W):
    if S > W:
        return "safe"
    return "unsafe"


S, W = list(map(int, input().split()))
print((issafe(S, W)))

def main():
    s, w = list(map(int, input().split()))
    if s > w:
        print("safe")
    else:
        print("unsafe")


main()

-def issafe(S, W): -    if S > W: -        return "safe" -    return "unsafe" +def main(): +    s, w = list(map(int, input().split())) +    if s > w: +        print("safe") +    else: +        print("unsafe") -S, W = list(map(int, input().split())) -print((issafe(S, W))) +main()