There are n boys and m girls attending a theatre club. To set a play "The Big Bang Theory", they need to choose a group containing exactly t actors containing no less than 4 boys and no less than one girl. How many ways are there to choose a group? Of course, the variants that only differ in the composition of the troupe are considered different.

Perform all calculations in the 64-bit type: long long for С/С++, int64 for Delphi and long for Java.

Input

The only line of the input data contains three integers n, m, t (4 ≤ n ≤ 30, 1 ≤ m ≤ 30, 5 ≤ t ≤ n + m).

Output

Find the required number of ways.

Please do not use the %lld specificator to read or write 64-bit integers in С++. It is preferred to use cin, cout streams or the %I64d specificator.

Examples

Input

5 2 5


Output

10


Input

4 3 5


Output

3
n, m, t = [int(x) for x in input().split()]


def c(x, y):
    num1 = 1
    num2 = 1
    for i in range(0, y):
        num1 = num1 * (x - i)
    for i in range(1, y + 1):
        num2 = num2 * i
    s = int(num1 / num2)
    return s



num = 0
s = min(t - 5, n - 4)
b = max(t - 4 - m, 0)
for i in range(b, s + 1):
    num += c(n, 4 + i) * c(m, t - 4 - i)
    i += 1
print(int(num))