1A

简单数学题，多考虑几个例子即可

def read():
    s = input()
    s = s.split(' ')
    s = [int(x) for x in s]
    return s

def write(data):
    print(data)
    

def calc(n, a):
    if n % a == 0:
        return n // a
    else:
        return n // a + 1
    
def solve(n, m, a):
    return calc(n, a) * calc(m, a)


data = read()
data = solve(data[0], data[1], data[2])
write(data)


# test 
assert(solve(6, 6, 4) == 4)

# small flagstore
assert(solve(1, 1, 1) == 1)

# big flagstore
assert(solve(10, 10, 100) == 1)

print('ok')