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 combi(int m, int k) {
  if (k > m) return 0;
  int x = min(k, m - k);
  long long ans = 1;
  for (int i = 1; i <= x; i++) ans = 1LL * ans * (m - i + 1) / i;
  return ans;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n, m, t;
  cin >> n >> m >> t;
  long long ans = combi(m + n, t) - combi(n, t) -
                  n * (n - 1) * (n - 2) / 6 * combi(m, t - 3) -
                  n * (n - 1) / 2 * combi(m, t - 2) - n * combi(m, t - 1) -
                  combi(m, t);
  cout << ans << endl;
}
