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 *

n, m, t = stdin.readline().split()
n = int(n)
m = int(m)
t = int(t)

ans = 0
for i in range(4, t):
  if (i > n):
    break
  if (t - i > m) or (t - i < 1):
    continue
  j = t - i
  ans += factorial(n) // factorial(i) // factorial(n - i) * factorial(m) // factorial(j) // factorial(m - j)
print(ans)