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() {
  vector<long long> pascal[61];
  long long n, m, t, x = 1;
  cin >> n >> m >> t;
  long long cant = 0, y;
  for (int i = 0; i < 61; i++) {
    pascal[i].push_back(1);
  }
  pascal[0].push_back(0);
  for (int i = 1; i < 61; i++) {
    for (int j = 1; j <= x; j++) {
      pascal[i].push_back(pascal[i - 1][j - 1] + pascal[i - 1][j]);
    }
    x++;
    pascal[i].push_back(0);
  }
  for (int i = 4; i < t; i++) {
    if (i <= n && (t - i) <= m) {
      y = pascal[n][i] * pascal[m][t - i];
      cant += y;
    }
  }
  cout << cant << endl;
}
