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 = map(int, raw_input().split())

answer = 0
 
for i in range(1, m+1):
    for j in range(4, n+1):
        if (i + j) == t:
          result = math.factorial(n)/(math.factorial(n - j) * math.factorial(j))
          result *= math.factorial(m)/(math.factorial(m - i) * math.factorial(i))
          answer += result

print answer

     	 			  				       	   	 	