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 com[35][35];
void pre() {
  for (int i = 0; i < 31; i++) com[i][0] = com[0][i] = 1;
  for (int i = 1; i < 31; i++)
    for (int j = 1; j <= i; j++)
      if (j != i)
        com[i][j] = com[i - 1][j] + com[i - 1][j - 1];
      else
        com[i][j] = 1;
}
int main() {
  int n, m, t;
  long long res;
  pre();
  while (cin >> n >> m >> t) {
    res = 0;
    int i = t - m < 4 ? 4 : t - m;
    for (; i < t && i <= n; ++i) res += com[n][i] * com[m][t - i];
    cout << res << endl;
  }
  return 0;
}
