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
n,m,t = map(int,input().split(' '))
result = 0
saida = 0
val = 4

def soma(n, m, result):
  result = 1
  for i in range(m):
    result *= int((n - i))
    result /= int((i + 1))
  return int(result)

while(val <= t-1):
  saida += soma(n,val,result) * soma(m,t - val,result)
  val += 1
  
print(saida)


	 		 	   	  		     				     	 	