You are given a trapezoid. The lengths of its upper base, lower base, and height are a, b, and h, respectively.    An example of a trapezoid  Find the area of this trapezoid.
a=[]
for i in range(3):
  a.append(int(input()))
  
print((a[0]+a[1])*a[2]/2)
a=[]
for i in range(3):
  a.append(int(input()))
  
print(int((a[0]+a[1])*a[2]/2))
