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
n, m, t = map(int, input().split())
if n < 4 or m < 1 or t < 5:
	print(0)
else:
	def f(x):
	    res = 1
	    if x == 0 or x == 1:
	        return res
	    while x > 1:
	        res = res * x
	        x -= 1
	    return res
	def binominal(k, n):
		return f(n) // (f(k) * f(n - k))    
	a = binominal(t, m + n)
	b = binominal(t, n)
	c = binominal(t, m) + binominal(1, n) * binominal(t - 1, m) + binominal(2, n) * binominal(t - 2, m) + binominal(3, n) * binominal(t - 3, m)
	print(a - b - c)