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;
long long n, m, t;
int main() {
  int i, j;
  long long res = 0;
  long long tmp;
  cin >> n >> m >> t;
  long long C[max(n, m) + 1][max(n, m) + 1];
  for (int j = 0; j <= max(n, m); ++j) {
    C[j][0] = 1;
    C[j][j] = 1;
    if (j == 0) continue;
    for (int k = 1; k < j; ++k) {
      C[j][k] = C[j - 1][k - 1];
      C[j][k] += C[j - 1][k];
    }
  }
  for (j = 0; j <= n; j++) {
    for (i = 0; i <= m; i++) {
      if (j >= 4 && i >= 1 && i + j == t) {
        tmp = C[n][j];
        tmp *= C[m][i];
        res += tmp;
      }
    }
  }
  cout << res;
}
