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 C[101][101];
  for (int i = 0; i <= 100; i++) {
    for (int j = 0; j <= i; j++) {
      if (j == 0 || j == i) {
        C[i][j] = 1;
      } else {
        C[i][j] = C[i - 1][j - 1] + C[i - 1][j];
      }
    }
  }
  int n, m, t;
  cin >> n >> m >> t;
  long long totalGirls = 0;
  long long totalBoys = 0;
  long long ways = 0;
  for (int i = 4; i <= n; i++) {
    if (t - i >= 1) {
      totalBoys += C[n][i];
      totalGirls += C[m][t - i];
      ways += (C[n][i]) * C[m][t - i];
    }
  }
  cout << ways << endl;
  return 0;
}
