import decimal

def main():
    N, M = map(int, input().split())
    P = decimal.Decimal(input())
    ans = 0
    if N == 1 and M == 1:
        ans = P
    elif N == 1:
        ans = (P ** 2) * 2 + P ** 3 * (M - 2)
    elif M == 1:
        ans = (P ** 2) * 2 + P ** 3 * (N - 2)
    else:
        ans += (P ** 3) * 4
        ans += (P ** 4) * ((N - 2) * 2 + (M - 2) * 2)
        ans += (P ** 5) * (N - 2) * (M - 2)

    print(ans)


if __name__ == "__main__":
    main()