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 math


def fac(n, a):
    res = a + 1

    for i in range(a + 2, n + 1):
        res = res * i

    return res


def comb(n, a):
    if n > a:
        fatN = fac(n, a)
        fatN_A = math.factorial(n - a)
        return fatN / (fatN_A)
    elif n == a:
        return 1
    else:
        return 0

h, m, num = map(int, raw_input().split())

i = 4
j = num - 4

res = 0

while j >= 1:
    res += comb(h, i) * comb(m, j)
    i += 1
    j -= 1

print res
 	  	  	   		   	 			 	 	     	