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 sol(long long int n, long long int k) {
  double res = 1;
  for (long long int i = 1; i <= k; ++i) res = res * (n - k + i) / i;
  return (long long int)(res + 0.01);
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  long long int n, m, t;
  cin >> n >> m >> t;
  long long int ans = 0;
  for (long long int nn = 4; nn <= n; nn++) {
    long long int mm = t - nn;
    if (mm > 0 && mm <= m) {
      cout << '\n';
      ans += (sol(n, nn) * sol(m, mm));
    }
  }
  cout << ans << '\n';
}
