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
def comb(n,m):
  total = 1
  for i in range(m):
    total = total*(n-i)/(i+1)
  return total

n,m,t = map(int,raw_input().split())

print comb(n+m,t)-comb(n,t) - comb(m,t) - comb(n,1)*comb(m,t-1)-comb(n,2)*comb(m,t-2)-comb(n,3)*comb(m,t-3)


		 	   	  	 	  			  			