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 n, m, t;
long long C(long long N, long long k) {
  double res = 1;
  for (long long i = 1; i <= k; ++i) res = res * (N - k + i) / i;
  return (long long)(res + 0.01);
}
void input() { cin >> n >> m >> t; }
void solve() {
  long long ans = 0;
  for (long long i = 4; i <= n; i++) {
    long long d = t - i;
    if (d < 1) break;
    ans += C(n, i) * C(m, d);
  }
  cout << ans;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.precision(20);
  long long T = 1;
  while (T--) {
    input();
    solve();
    cout << endl;
  }
  cin.get();
  return 0;
}
