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
#!/usr/bin/env python
# -*- coding: utf-8 -*-

from collections import defaultdict
from math import factorial as f
from fractions import gcd as g

n, m, t = [int (i) for i in raw_input ().split ()]
def combi (n, r):
    c = 1
    if n - r > 0: c = f (n - r)
    return f (n) / f (r) / c
# print combi (m - 1, t - 5)
ret = 0
for boys in range (4, n + 1):
    for girls in range (1, m + 1):
        if boys + girls == t:
            ret += combi (n, boys) * combi (m, girls)
print ret
