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;
const long long MX = 10e12 + 1;
long long Combinators(int n, int m) {
  if (m == 0) return 1;
  return n * Combinators(n - 1, m - 1) / m;
}
void Solution() {
  int n, m, t;
  cin >> n >> m >> t;
  long long res = 0;
  for (int i = 4; i < t; ++i) res += Combinators(n, i) * Combinators(m, t - i);
  cout << res;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  Solution();
  return 0;
}
