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
# 2011
# Maciej Szeptuch
# II UWr
import sys

def factorial(a):
	result = 1
	for i in range(2, a + 1):
		result *= i

	return result

def binomial(n, k):
	if k > n:
		return 0

	return factorial(n) / factorial(n - k) / factorial(k)

boys, girls, group = sys.stdin.read().split()
boys = int(boys)
girls = int(girls)
group = int(group)

print >>sys.stdout, binomial(boys + girls, group) - binomial(boys, 0) * binomial(girls, group) - binomial(boys, 1) * binomial(girls, group - 1) - binomial(boys, 2) * binomial(girls, group - 2) - binomial(boys, 3) * binomial(girls, group - 3) - binomial(girls, 0) * binomial(boys, group)
