def input_side():
while True:
raw_input = input("Enter the side of a square in centimeters: ")
try:
side = float(raw_input)
except ValueError:
print(f"{raw_input} is not a number!")
else:
if side <= 0:
print(f"{raw_input} is a negative number!")
else:
break
return side
side = input_side()
print(f"The perimeter of a square with a side of {side} cm is {side * 4} cm.")
print(f"The area of a square with a side of {side} cm is {side ** 2} cm2.")