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 fatorial(max):
  fatoriais = [1]
  for i in range(1, max):
    fatoriais.append(fatoriais[-1] * i)
  return fatoriais

def combinatoria(n, p):
  return fatoriais[n] // (fatoriais[n - p] * fatoriais[p]);

num_de_garotos, num_de_garotas, num_de_atores = map(int, input().split())

fatoriais = fatorial(35)
limite = min(num_de_garotos, num_de_atores - 1)
possibilidades = 0
for i in range(4, limite + 1):
  if ((num_de_atores - i) <= num_de_garotas):
    garotos = combinatoria(num_de_garotos, i)
    garotas = combinatoria(num_de_garotas, num_de_atores - i)
    possibilidades = possibilidades + garotos * garotas
print(possibilidades)
  		  	 	  		  	 	  	  				   	