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 comb(a, b):
	if(a == b):
		return 1
	v = 1
	for i in range(a, a-b, -1):
		v *= i
	for i in range(2, b+1):
		v /= i
	return v

ler = raw_input().split()
n = int(ler[0]) 
m = int(ler[1])
t = int(ler[2])

tot = comb(n+m, t)
nowm = comb(n, t)
m3 = 0
m2 = 0
m1 = 0
m0 = 0

if m >= t-3:
	m3 = comb(m, t-3) * comb(n, 3)

if m >= t-2:
	m2 = comb(m, t-2) * comb(n, 2)

if m >= t-1:
	m1 = comb(m, t-1) * n

if m >= t:
	m0 = comb(m, t)

res = tot - nowm - (m3 + m2 + m1 + m0)

print res
