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
from math import *
choose = lambda n,m: factorial(n)/factorial(m)/factorial(n - m)

cnt = 0
boy,girl,t = map(int,raw_input().split())
for boy_num in xrange(4,t):
	girl_num = t - boy_num
	if 0 <= girl_num <= girl and 0 <= boy_num <= boy:
		cnt = cnt + choose(boy,boy_num) * choose(girl,girl_num)
print cnt 
	 		    	 			    	  	  				 			