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
#-*- coding: utf-8 -*-
import sys

w = sys.stdout.write
read = sys.stdin.readline
reads = sys.stdin.read

def r(f=None):
    if f:
        return map(f, read().split())
    else:
        return read().split()

def rs(t,f=None):
    result = []
    result_append = result.append
    for i in xrange(t):
        if f:
            result_append(map(f, read().split()))
        else:
            result_append(read().split())
    return result


####################################################

[n, m, t] = r(int)

def choose(n, k):
    if 0 <= k <= n:
        ntok = 1
        ktok = 1
        for t in xrange(1, min(k, n - k) + 1):
            ntok *= n
            ktok *= t
            n -= 1
        return ntok // ktok
    else:
        return 0

bb = {}
for b in range(4, min(n+1, t+1), 1):
    bb[b] = choose(n, b)
gg = {}    
for g in range(1, min(m+1, t+1), 1):
    gg[g] = choose(m, g)
k = 0
for b in bb:
    k += bb[b] * gg.get(t-b, 0)
    
w(str(k))
    
    