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
homens, mulheres, h = map(int, raw_input().split())
soma = 0

def fat(a):
  if a == 0 or a == 1:
    return 1
  else:
    return a*fat(a-1)


def possibilidades(a, b):
  return fat(a)/(fat(b)*fat(abs(a-b)))


for i in xrange(4, h):
  soma += possibilidades(homens, i)*possibilidades(mulheres, h-i)

print soma