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[31][31];
void pascal() {
  for (int line = 0; line < 31; line++) {
    for (int i = 0; i <= line; i++) {
      if (line == i || i == 0) {
        com[line][i] = 1;
      } else {
        com[line][i] = com[line - 1][i - 1] + com[line - 1][i];
      }
    }
  }
}
int main() {
  int n, m, t;
  pascal();
  cin >> n >> m >> t;
  long long c = 0;
  for (int i = 4; i < n + 1; i++) {
    for (int j = 1; j < m + 1; j++) {
      if (i + j == t && i >= 4 && j >= 1) {
        c += (com[n][i] * com[m][j]);
      }
    }
  }
  cout << c;
}
