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
def fatorial(n):
    if n < 2:
        return 1
    return n * fatorial(n-1)

def comb_p(n, p):
    if n > p:
        return (fatorial(n)) / ((fatorial(p) * (fatorial(n-p))))
    elif n == p:
        return 1
    else:
        return 0

b, g, tam = list(map(int, raw_input().split()))
retorno = 0

max_b = min(tam - 1, b)
min_g = tam - max_b

while True:
    if min_g > g or max_b < 4:
        break

    retorno += comb_p(b, max_b) * comb_p(g, min_g)

    max_b -= 1
    min_g += 1

print(int(retorno))
	   		 	  	 	     	 	   	 	 	 	