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 c(int x, int y) {
  long long ans = 1;
  for (int i = 0; i < x; i++) ans = ans * (y - i) / (i + 1);
  return ans;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n, m, t;
  cin >> n >> m >> t;
  long long ans = 0;
  int start = max(4, t - m);
  int limit = min(t - 1, n);
  for (int i = start; i <= limit; ++i) {
    int j = t - i;
    ans += c(i, n) * c(j, m);
  }
  cout << ans << "\n";
  return 0;
}
