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
#include <bits/stdc++.h>
long long choose(int n, int r) {
  return r == 0 ? 1 : choose(n - 1, r - 1) * n / r;
}
int main() {
  int n, m, t, b;
  long long ans;
  scanf("%d%d%d", &n, &m, &t);
  ans = 0;
  for (b = 4; b <= n && b + 1 <= t; b++)
    if (t - b <= m) ans += choose(n, b) * choose(m, t - b);
  printf("%lld\n", ans);
  return 0;
}
