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;
unsigned long long d[30 + 2][30 + 2], ans = 0;
int main() {
  int n, m, t;
  cin >> n >> m >> t;
  for (int i = 0; i < 32; i++)
    for (int j = 0; j < 32; j++)
      if (j == 0)
        d[j][i] = 1;
      else if (i < j)
        d[j][i] = 0;
      else if (i == j)
        d[j][i] = 1;
      else
        d[j][i] = d[j - 1][i - 1] + d[j][i - 1];
  for (int i = 4; i <= n; i++)
    if (((t - i) >= 1) && ((t - i) <= m)) ans += d[i][n] * d[t - i][m];
  cout << ans << endl;
  return 0;
}
