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 arr[300][300];
void precal() {
  arr[0][0] = 1;
  for (int i = 1; i < 32; ++i) {
    arr[i][0] = 1;
    for (int j = 1; j <= i; ++j) {
      arr[i][j] = (arr[i - 1][j] + arr[i - 1][j - 1]);
    }
  }
}
int main() {
  precal();
  int t, m, n;
  cin >> t >> m >> n;
  long long int sum = 0;
  for (int i = 4; i < n; ++i) {
    sum += (arr[t][i] * arr[m][n - i]);
  }
  cout << sum;
  return 0;
}
