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 com[100 + 1][100 + 1];
int main() {
  int t, n, r;
  for (int i = int(0); i <= int(100); i++) com[i][0] = 1;
  for (int i = int(1); i <= int(100); i++) {
    for (int j = int(1); j <= int(i); j++) {
      com[i][j] = com[i - 1][j - 1] + com[i - 1][j];
    }
  }
  int m;
  while (cin >> n >> m >> t) {
    long long ans = 0;
    for (int j = 4; j <= n; j++) {
      if (j > t) break;
      int k = t - j;
      if (k > m || k < 1) continue;
      ans += com[n][j] * com[m][k];
    }
    cout << ans << endl;
  }
  return 0;
}
