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>
const int sze = 2e3 + 5;
const long long int mod = 1e18;
using namespace std;
long long int n, i, j, k, md, hi, lo, s, m, r, mx, h, flag, u, ans1, l, sum, x,
    t, y, w, ans, q, hsh;
long long int a[50][50];
pair<long long int, long long int> p[100008];
int main() {
  ios::sync_with_stdio(false);
  cin >> n >> m >> t;
  for (i = 0; i <= max(n, m); i++) {
    for (j = 0; j <= i; j++) {
      if (i == 0 || j == 0 || j == i) {
        a[i][j] = 1;
      } else {
        a[i][j] = a[i - 1][j] + a[i - 1][j - 1];
      }
    }
  }
  for (i = 4; i <= n; i++) {
    if (t - i > 0 && t - i <= m) {
      ans += a[m][t - i] * a[n][i];
    }
  }
  cout << ans << endl;
  return 0;
  ;
}
