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 n, m, t;
long long a[50][50], ans;
int main() {
  cin >> n >> m >> t;
  int k = max(n, m);
  for (int i = 0; i <= k; i++)
    for (int j = 0; j <= i; j++)
      if (i == 0 || j == 0 || j == i)
        a[i][j] = 1;
      else
        a[i][j] = a[i - 1][j] + a[i - 1][j - 1];
  for (int i = 4; i <= t - 1; i++) {
    if (t - i <= m && i <= n) ans += a[n][i] * a[m][t - i];
  }
  cout << ans;
  return 0;
}
