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 sys
import math
import functools
from fractions import Decimal

@functools.lru_cache(maxsize=None)
def bf(n,m,t):
	if t == T:
		sol.append((n+4,m+1))
	if n < N:
		bf(n+1,m,t+1)
	if m < M:
		bf(n,m+1,t+1)


@functools.lru_cache(maxsize=None)
def fact(n):
	if n <= 1:
		return Decimal(1)
	n = Decimal(n)
	return n*fact(n-1)

def k_parmi_n(k,n):
	return Decimal(fact(n)/(fact(k)*fact(n-k)))
N,M,T = list(map(int, sys.stdin.readline().strip().split(' ')))

N -= 4
M -= 1
T -= 5

sol = []
ans = 0
bf(0,0,0)

N += 4
M += 1

for (n,m) in sol:
	ans += Decimal(k_parmi_n(n,N) * k_parmi_n(m,M))
print(int(ans))

