a035. 伏林的三角地 | From: [192.168.120.33] | Post Date : 2024-03-15 11:33

a=input()
b=a.split()
d=int(0.5*(int(b[0])+int(b[1])+int(b[2])))
e=(d*(d-int(b[0]))*(d-int(b[1]))*(d-int(b[2])))
print(e)