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
#!/usr/bin/env python3

def fact(n):
	ans = 1
	for i in range(2, n+1):
		ans *= i
	return ans

def c(k, n):
	return fact(n) // fact(k) // fact(n-k)

n, m, t = map(int, input().split())
ans = 0
for men in range(4, min(n, t-1)+1):
	women = t - men
	ans += c(men, n) * c(women, m)
print(ans)
