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 fact(n):
	res = 1
	for i in range(1, n + 1):
		res = res * i
	return res

def C(n, k):
        #if k > n:
        #	return -1
	res = fact(n)/(fact(k)*fact(n - k))
	return int(res)

from sys import stdin
__inp = stdin.readline().split(' ')
N = int(__inp[0])
M = int(__inp[1])
T = int(__inp[2])

res = 0
for i in range(4, T):
	res += C(N, i)*C(M, T - i)

print(int(res))
'''
for i in range(1, 31):
	print('{', end='')
	for j in range(1, 31):
		print(C(i, j), sep='', end=', ')
	print(C(i, i), '}, ', end='', sep='')
'''
	
