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
__author__ = 'xywang'
import sys
import math


class CodeForces:
    def nCr(self, n,r):
        f = math.factorial
        return f(n) / f(r) / f(n-r)
    def getResult(self):
        n, m, t = map(long, sys.stdin.readline().split(" "))
        result = 0
        for i in range(4, t):
            if i > n or t - i > m:
                continue
            result += self.nCr(n, i) * self.nCr(m, t - i)
        print result







def main():
    code = CodeForces()
    code.getResult()

if __name__ == "__main__":
    main()