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 nCr(int n, int r) {
  if (r == 0) return 1;
  return n * nCr(n - 1, r - 1) / r;
}
int main() {
  long long b, g, t, i = 4, ans = 0;
  cin >> b >> g >> t;
  while (i < t) ans += nCr(b, i) * nCr(g, (t - i)), i++;
  cout << ans << endl;
  return 0;
}
