import math
# BEGIN (write your solution here)
x = input('x=')
figure = input('figure=')
square = 0.0

try:
    x = float(x)
except:
    print ('error')
    exit(1)

if x <= 0:
    print ('error')
    exit(1)

if  figure == 'circle':
    square = math.pi * x * x
    print ('The area is %.2f' % square)
    exit(0)
elif figure == 'square':
    square = x * x
    print ('The area is %.2f' % square)
    exit(0)
else:
    print ('error')
    exit(1)
# END