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
n, m, t = map(int, raw_input().split())
min_guys = 4
min_girls = 1

import operator as op
def ncr(n, r):
    r = min(r, n-r)
    if r == 0: return 1
    numer = reduce(op.mul, xrange(n, n-r, -1))
    denom = reduce(op.mul, xrange(1, r+1))
    return numer//denom
    
if t < 5:
    print('0')
else:
    total = 0
    #For 6 -> 4 boys 2 girls, 5 boys 1 girl
    for num_boys in xrange(min_guys, t):
        for num_girls in xrange(min_girls, t):
            if (num_boys + num_girls == t and
                num_boys <= n and num_girls <= m):
                total += ncr(n, num_boys) * ncr(m, num_girls)
    print(total)
