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 int cm(int n, int k) {
  if (k > n) {
    return 0;
  }
  long long int r = 1;
  for (int d = 1; d <= k; ++d) {
    r *= n--;
    r /= d;
  }
  return r;
}
int main() {
  int n, m, t;
  cin >> n >> m >> t;
  int b, g;
  long long int count = 0;
  for (b = 4; b <= t - 1; b++) {
    for (g = 1; g <= t - 4; g++) {
      if (b + g == t) {
        count += cm(n, b) * cm(m, g);
      }
    }
  }
  cout << count << endl;
  return 0;
}
