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 tc, cs = 1;
long long int com[41][41];
void Set() {
  com[0][0] = 1;
  for (int i = 1; i < 41; i++) {
    com[i][0] = 1;
    com[i][i] = 1;
    for (int j = 1; j < i; j++) com[i][j] = com[i - 1][j] + com[i - 1][j - 1];
  }
}
int main() {
  int t, n, m;
  long long int way = 0;
  Set();
  cin >> n >> m >> t;
  for (int i = 4; i < n + 1; i++)
    for (int j = 1; j < m + 1; j++)
      if (i + j == t) way += (com[n][i] * com[m][j]);
  cout << way << endl;
  return 0;
}
