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.
The only line of the input data contains three integers *n*, *m*, *t* (4 ≤ *n* ≤ 30, 1 ≤ *m* ≤ 30, 5 ≤ *t* ≤ *n* + *m*).
5 2 5
10
4 3 5
3
4 1 5
1
7 3 6
168
30 30 30
118264581548187697
10 10 8
84990
10 10 10
168229
10 10 20
1
20 15 27
23535820
20 20 40
1
20 20 24
62852101650
4 20 20
4845
4 20 24
1
20 3 23
1
20 1 21
1
20 1 5
4845
20 20 5
96900
30 30 60
1
30 30 59
60
30 29 55
455126
30 29 59
1
4 30 34
1
30 1 20
54627300
30 1 31
1
29 30 57
1711
25 30 40
11899700525790
4 2 6
1
5 1 6
1
30 30 50
75394027566
30 30 57
34220
30 30 58
1770
25 25 48
1225
30 1 30
30
28 28 50
32468436
28 28 55
56
30 30 55
5461512
7 30 37
1
10 1 11
1
10 1 6
252
from os import path
from sys import stdin, stdout
from typing import List

filename = "../templates/input.txt"
if path.exists(filename):
    stdin = open(filename, 'r')


def input():
    return stdin.readline().rstrip()


def print(*args, sep=' ', end='\n'):
    stdout.write(sep.join(map(str, args)))
    stdout.write(end)


def pascal_triangle(n: int) -> List[List[int]]:
    """
    returns pascal triangle
    which element [n][k] is the binomial coefficient
    or number of ways for selecting k elements out of n options without order
    """
    ans = [[0 for j in range(n + 1)] for i in range(n + 1)]
    for i in range(n + 1):
        ans[i][0] = 1
    for i in range(1, n + 1):
        for j in range(1, n + 1):
            ans[i][j] = ans[i - 1][j - 1] + ans[i - 1][j]
    return ans


def solution():
    n, m, t = [int(num) for num in input().split()]
    pt = pascal_triangle(30)
    ans = 0
    for j in range(1, m + 1):
        i = t - j
        if 4 <= i <= n:
            ans += pt[m][j] * pt[n][i]
    print(ans)


def main():
    t = 1
    while t:
        solution()
        t -= 1


if __name__ == '__main__':
    main()
