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 python

n,m,t = map(long, raw_input().strip().split())

from operator import mul
nCk = lambda n,k: int(round(
     reduce(mul, (float(n-i)/(i+1) for i in range(k)), 1)
))

res = 0
for x in xrange(4,n+1):
	for y in xrange(1,m+1):
		if y+x==t:
			res += nCk(n,x)*nCk(m,y)

print res

