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__ = 'cshui'

import sys
import heapq
import re
from collections import defaultdict

class PriorityQueue:
    def __init__(self):
        self._queue = list()
        self._index = 0

    '''
    def push(self, item, priority):
        heapq.heappush(self._queue, (priority, self._index, item))
        self._index += 1
    '''
    def push(self, item):
        heapq.heappush(self._queue, item)

    def pop(self):
#        return heapq.heappop(self._queue)[-1]
        return heapq.heappop(self._queue)

    def printq(self):
        print self._index, self._queue

'''
with open('genpath.log') as f:
    lines = f.readlines()
'''

def gcd(a, b):
    """Return greatest common divisor using Euclid's Algorithm."""
    while b:
        a, b = b, a % b
    return a

def lcm(a, b):
    """Return lowest common multiple."""
    return a * b // gcd(a, b)

def lcmm(*args):
    """Return lcm of args."""
    return reduce(lcm, args)

def comb(n, r):
    rc = 1
    if r > (n >> 2):
        r = n - r
    for i in range(1, r+1):
        rc = rc * (n-r+i) // i
#        print i, ': ', n-r+i, i, rc
#    print n, r, rc
    return rc

#lines = [ line for line in sys.stdin ]
#lines = ['4', '75 150 75 50']            # Yes
#lines = ['3','536870912 387420489 257407169']
#lines = ['3', '100 150 250']             # No
#din = [5, 5, 3, 2]                     # 2

#din = [100, 3, 17, 22]                 #27
#din = [29, 27, 18, 2]                  # 2
#din = [53, 10, 11, 23]                 # 5
#din = [5, 2, 5]                 # 10
#din = [4, 3, 5]                 # 3
#din = [10, 10, 20]              # 1

din = map(int, raw_input().split())
'''
n = int(lines[0].strip())
bets = [int(x) for x in lines[1].strip().split()]

#print 2**64-1
'''

(n, m, t) = din

if t > n:
    s = t - n
else:
    s = 1
if t - m < 4:
    l = t - 4
else:
    l = m
result = 0
for i in  range(s, l+1):
    result += comb(m, i) * comb(n, t-i)
print result