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 math

n,m,t = [int(x) for x in raw_input().split()]

boys = 4

total = 0


def combs(boys, girls, t):

  if boys < 0 or girls < 0:
    return 0

  if n - boys < 0 or m - girls < 0:
    return 0
	
  if boys + girls != t:
    return 0

	
  bc = math.factorial(n)/(math.factorial(boys) * (math.factorial(n - boys)))
  
  
  gc = math.factorial(m)/(math.factorial(girls) * (math.factorial(m - girls)))

  
  
  return bc * gc  
    

while True:

  if boys + 1 > t:
    break
	
  total += combs(boys, t - boys, t)
  boys += 1  
  
print total  