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
# ///==========Libraries, Constants and Functions=============///
#mk_Raghav
import sys

inf = float("inf")
mod = 1000000007


def get_array(): return list(map(int, sys.stdin.readline().split()))


def get_ints(): return map(int, sys.stdin.readline().split())


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

def int1():return int(input())

import string

import math
# ///==========MAIN=============///
n,m,t=get_array()

def main():
    def nCr(n,r):
        return (math.factorial(n) // math.factorial(r)// math.factorial(n-r))
    i=4
    j=t-i
    z=0
    while j+i<=t:
        if i<=n and j<=m:

            z=z+nCr(n,i)*nCr(m,j)
        i=i+1
        j=t-i


        if i>n  or  j<1:
            break


    print(z)




if __name__ == "__main__":
    main()
