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 nCr(long long int n, long long int r) {
  r = min(r, n - r);
  long long int ans = 1;
  long long int val = 1;
  for (long long int i = 1; i <= r; i++) {
    val *= i;
  }
  for (long long int i = 0; i < r; i++) {
    ans *= (n - i);
    if (ans % val == 0) {
      ans /= val;
      val = 1;
    }
  }
  return ans / val;
}
signed main() {
  long long int n, m, t, ways;
  cin >> n >> m >> t;
  ways = 0;
  for (long long int i = 4; i <= n; i++) {
    for (long long int j = 1; j <= m; j++) {
      if (i + j == t) {
        ways += nCr(n, i) * nCr(m, j);
      }
    }
  }
  cout << ways << endl;
  return 0;
}
