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() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, m, t;
  cin >> n >> m >> t;
  if (t > m + n || n < 4 || m < 1) {
    cout << "0";
    return 0;
  }
  long long int ans = 0;
  long long int b[31][31] = {0};
  for (int i = 0; i < 31; i++) {
    b[i][i] = 1;
    b[i][0] = 1;
  }
  for (int i = 2; i < 31; i++) {
    for (int r = 1; r < i; r++) {
      b[i][r] = b[i - 1][r - 1] + b[i - 1][r];
    }
  }
  for (int i = 4; i <= n; i++) {
    if ((t - i < 1) || (t - i > m)) {
      continue;
    }
    ans += b[n][i] * b[m][t - i];
  }
  cout << ans;
}
