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
from sys import*
from math import*

a = list(map (int, stdin.readline().split()))
n = a[0];
m = a[1];
t = a[2];
ans = int(0);
for i in range(4, n+1):
  j = t - i;
  if j < 1:
    break
  if (j > 0) & (n-i >= 0) & (m-j >= 0):
    ans+= int(factorial(n)/(factorial(i)*factorial(n-i)) * factorial(m)/(factorial(j)*factorial(m-j)))
print(ans)