a = float(input())
b = float(input())
print((a+b)/2)
def S(r):
return 3.14 * r**2
r = float(input())
print(S(r))
print(3.14 * r**2)
a = float(input())
b = float(input())
print((a+b)/2)
def S(r):
return 3.14 * r**2
r = float(input())
print(S(r))
r = float(input())
print(3.14 * r**2)