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;
int dd[200];
long long cnm(long long n, long long m) {
  long long i, tmp1, tmp2, tes, tt;
  if (n == 0 || m == 0) return 0;
  if (n == m) return 1;
  if (n - m < m) m = n - m;
  for (tmp1 = 1, tt = 1, i = n - m + 1; i <= n; i++, tt++) {
    tmp1 *= i;
    tmp1 /= tt;
  }
  return (tmp1);
}
int main() {
  long long res, tmp1, tmp2;
  long long n, m, t, i;
  cin >> n >> m >> t;
  res = 0;
  tmp1 = ((t - 1) < (n) ? (t - 1) : (n));
  for (i = tmp1; i >= 4; i--) {
    if (t - i > m) break;
    res += cnm(n, i) * cnm(m, t - i);
  }
  cout << res << endl;
  return 0;
}
