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;
int main() {
  long long **arr = new long long *[61];
  for (int i = 0; i <= 61; i++) {
    arr[i] = new long long[i + 1];
    for (int j = 0; j <= i; j++) {
      if (j == 0 or j == i) {
        arr[i][j] = 1;
        continue;
      }
      arr[i][j] = arr[i - 1][j - 1] + arr[i - 1][j];
    }
  }
  int n, m, t;
  cin >> n >> m >> t;
  long long ans = arr[n + m][t];
  if (t <= m) {
    ans -= (arr[n][0] * arr[m][t]);
  }
  if (t - 1 <= m) {
    ans -= (arr[n][1] * arr[m][t - 1]);
  }
  if (t - 2 <= m) {
    ans -= (arr[n][2] * arr[m][t - 2]);
  }
  if (t - 3 <= m) {
    ans -= (arr[n][3] * arr[m][t - 3]);
  }
  if (n >= t) {
    ans -= (arr[n][t] * arr[m][0]);
  }
  cout << ans << endl;
  return 0;
}
