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 n == 1:
        ans = p
    elif m == 1:
        cp = p ** 2
        ep = p ** 3
        ans = cp * 2 + ep * (n - 2)
    else:
        cp = p ** 3
        ep = p ** 4
        ip = p ** 5
        ans = cp * 4 + ep * 2 * (n + m - 4) + ip * (n - 2) * (m - 2)
    print(ans)

main()