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
import sys

def F(n):
    if n == 0: return 1
    if n == 1: return 1
    return n * F(n - 1)

def P(n, l):
    answ = 1
    for i in range(l + 1, n + 1):
        answ *= i
    return answ

def C(n, m):
    if n == m : return 1
    if m == 1 : return n
    return int(P(n, max(n - m, m)) / F(min(n - m, m)))

def main():
    n, m, t = [int(i) for i in input().split()]

    if t == (n + m):
        print(1)
        sys.exit(0)

    answ = 0

    for i in range(max(4, t - m), min(n + 1, t)):
        answ += C(n, i) * C(m, t - i)

    print(answ)
    return 0

if __name__ == '__main__':
    main()
