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 n, int k) {
  if (k > n) return 0;
  if (k * 2 > n) k = n - k;
  if (k == 0) return 1;
  long long result = n;
  for (int i = 2; i <= k; ++i) {
    result *= (n - i + 1);
    result /= i;
  }
  return result;
}
int main() {
  int n, m, t;
  long long tot = 0;
  cin >> n >> m >> t;
  for (int b = 4; b <= n; ++b) {
    int g = t - b;
    if (g >= 1) {
      tot += c(n, b) * c(m, g);
    }
  }
  cout << tot << endl;
  return 0;
}
