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;
int arr[100][100];
long long int combi(long long int n, long long int k) {
  if (k > n) return 0;
  if (k * 2 > n) k = n - k;
  if (k == 0) return 1;
  if (arr[n][k]) return arr[n][k];
  long long int res = n;
  for (long long int i = 2; i <= k; i++) {
    res *= (n - i + 1);
    res /= i;
  }
  arr[n][k] = res;
  return res;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  memset(arr, 0, sizeof(arr));
  long long int n, m, t;
  cin >> n >> m >> t;
  long long int ans = 0;
  long long int j = t - 1;
  for (long long int i = 1; i <= t - 4; i++) {
    ans += combi(n, j) * combi(m, i);
    j--;
  }
  cout << ans << "\n";
  return 0;
}
