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 n, m, t;
long long ans, c[100][100];
long long f(int r, int n) {
  if (c[r][n] != -1) return c[r][n];
  if (r > n) return c[r][n] = 0;
  if (r == 0 || r == n) return c[r][n] = 1ll;
  return c[r][n] = f(r - 1, n - 1) + f(r, n - 1);
}
int main() {
  ios::sync_with_stdio(false), cin.tie(0);
  for (int i = 0; i < 31; i++)
    for (int j = 0; j < 31; j++) c[i][j] = -1;
  cin >> n >> m >> t;
  for (int i = 4; i <= min(t - 1, n); i++) ans += f(i, n) * f(t - i, m);
  cout << ans << endl;
}
