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 ncr(int n, int r) {
  if (n - r < r) r = n - r;
  long long int res = 1;
  for (int i = 1; i <= r; i++) {
    res = res * n;
    res = res / i;
    n--;
  }
  return res;
}
int main() {
  int n, m, t;
  cin >> n >> m >> t;
  long long int sum = 0;
  for (int i = 4; i <= n; i++) {
    for (int j = 1; j <= m && (i + j <= t); j++) {
      if (i + j == t) {
        sum = sum + (ncr(n, i) * (ncr(m, j)));
      }
    }
  }
  cout << sum << endl;
}
