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;
const int siz = 30 + 2;
long long a[siz][siz];
int main() {
  int n, m, t;
  cin >> n >> m >> t;
  for (int i(1); i <= (siz - 1); i++)
    for (int j(0); j <= (i); j++) {
      if (j == 0 || j == i)
        a[i][j] = 1;
      else
        a[i][j] = a[i - 1][j] + a[i - 1][j - 1];
    }
  long long sum = 0;
  for (int i(4); i <= (n); i++)
    for (int j(1); j <= (m); j++) {
      if (i + j == t) sum += a[n][i] * a[m][j];
    }
  cout << sum << endl;
}
