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>
using namespace std;
long long int n, m, k, i, j, t;
long long f(int n, int m) {
  if (m > n) return 0;
  double t = 1;
  m = min(m, n - m);
  for (int i = 1; i <= m; i++) t = t * (n - i + 1) / i;
  return (long long)t;
}
int main() {
  long long int t = 0;
  cin >> n >> m >> k;
  for (i = 4; i < k; i++) t += f(n, i) * f(m, k - i);
  cout << t;
  return 0;
}
