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 pascal[31][31];
int main(void) {
  int n, m, t;
  cin >> n >> m >> t;
  pascal[0][0] = 1;
  pascal[1][0] = pascal[1][1] = 1;
  for (int i = 2; i <= 30; i++) {
    pascal[i][0] = 1;
    for (int j = 1; j < i; j++) {
      pascal[i][j] = (pascal[i - 1][j - 1] + pascal[i - 1][j]);
    }
    pascal[i][i] = 1;
  }
  long long int tot = 0;
  for (int cm = 4; cm <= min(t, n); cm++) {
    int cw = t - cm;
    if (t - cm <= m && cw >= 1) {
      tot += (pascal[n][cm] * pascal[m][cw]);
    }
  }
  cout << tot << endl;
  return 0;
}
