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
fact = []
fact.append(1)
fact.append(1)
for i in range(2,31):
	fact.append(fact[i-1]*i)

def ncr(n,r):
	if r>n:
		return 0
	if r==n:
		return 1
	return fact[n]//(fact[n-r]*fact[r])



n,m,t = input().split()
n = int(n)
m = int(m)
t = int(t)

if n<4 or m<1 or t<5:
	print("0")
else:
	ans = 0;
	for i in range(4,t):
		if t-i>=1:
		    ans = ans + ncr(n,i)*ncr(m,t-i)
	print(int(ans))