import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def MI(): return map(int, sys.stdin.readline().split())
def MF(): return map(float, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LF(): return list(map(float, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]

def main():
    n,m=MI()
    p = float(input())
    if n<m:n,m=m,n
    if m>1:
        cp=p**3
        ep=p**4
        ip=p**5
        ans=cp*4+ep*2*(n+m-4)+ip*(n-2)*(m-2)
    else:
        cp=p**2
        ep=p**3
        ans=cp*2+ep*(n-2)
    print(ans)

main()