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 math

def nCr(n,r):
    f = math.factorial
    return int(f(n)/(f(r)*f(n-r)))





R = lambda :list(map(int,input().split()))
n,m,t = R()
s = 0
for h in range(4,t) :
	if t-h <= m and h <= n:
		s += (nCr(n,h)*nCr(m,t-h))

print(s)