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
from collections import defaultdict
import os,io
from sys import stdout
import math
input = io.BytesIO(os.read(0,os.fstat(0).st_size)).readline
from fractions import Fraction
from decimal import *

def choose(n, k):
    """
    A fast way to calculate binomial coefficients by Andrew Dalke (contrib).
    """
    if 0 <= k <= n:
        ntok = 1
        ktok = 1
        for t in range(1, min(k, n - k) + 1):
            ntok *= n
            ktok *= t
            n -= 1
        return ntok // ktok
    else:
        return 0

def choose2(n, k):
    n = Decimal(n)
    k = Decimal(k)
    return Decimal(math.factorial(n)) / (Decimal(math.factorial(k)) * Decimal(math.factorial(n-k)))

n, m, t = list(map(int, input().split()))
s = 0
for i in range(1, m+1):
    fc = choose(m, i)
    boysToTake = t - i
    if boysToTake < 4 or boysToTake > n:
        continue
    bc = choose(n, boysToTake)
    s += fc * bc
print(s)
