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
import math

cache = {}


def factorial(k):
    if k == 0:
        return 1
    if k == 1:
        return 1
    if k in cache:
        return cache[k]
    ans = factorial(k - 1) * k
    cache[k] = ans
    return ans


def choose(n, k):
    return factorial(n) // (factorial(n - k) * factorial(k))


def solve(n, m, t):
    minBoys = 4
    minGirls = 1
    possibilities = 0
    for boys in range(minBoys, n + 1):
        necGirls = t - boys
        if minGirls <= necGirls <= m:
            possibilities += choose(n, boys) * choose(m, necGirls)
    return possibilities


def readinput():
    n, m, t = map(int, sys.stdin.readline().rstrip().split(" "))
    print(solve(n, m, t))


readinput()
