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
import sys
input = sys.stdin

def factorial(n):
  res = 1
  for k in xrange(1, n+1):
    res *= k
  return res

def subsets(n, k):
  return factorial(n) / factorial(n - k) / factorial(k)

[BOYS, GIRLS, SIZE] = map(int, input.readline().split())

res = 0
boys = SIZE
girls = 0

while boys >= 0:
  if boys >= 4 and girls >= 1:
    res += subsets(BOYS, boys) * subsets(GIRLS, girls)
  boys -= 1
  girls += 1

print res
