while True:
try:
year = int(input()) # "Please enter a year: "
except ValueError:
print("Not a valid integer.")
break
else:
if not year%100:
if not year%400:
print(year, "leap year")
else:
print(year, "NOT leap year")
elif not year%4:
print(year, "leap year")
else:
print(year, "NOT leap year")