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

from operator import mul    # or mul=lambda x,y:x*y
from fractions import Fraction

def nCk(n,k): 
    return int( reduce(mul, (Fraction(n-i, i+1) for i in range(k)), 1) )


def bigBangTheory():
    nBoys, nGirls, t = map(int, sys.stdin.readline().split())
    # print 
    tot = 0
    maxGirls = min(nGirls, t-4)
    for iGirls in range(1, maxGirls + 1):
        # print "iGirls", iGirls, "add", nCk(nGirls, iGirls) * nCk(nBoys, t - iGirls)
        tot += nCk(nGirls, iGirls) * nCk(nBoys, t - iGirls)
    print tot

bigBangTheory()

