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>
int main() {
  long long pascal[31][31];
  long long i, j, r = 0, n, m, t;
  for (i = 0; i < 31; i++) {
    pascal[0][i] = 1;
    pascal[i][i] = 1;
  }
  for (j = 1; j < 31; j++) {
    for (i = 1; i < j; i++) {
      pascal[i][j] = pascal[i][j - 1] + pascal[i - 1][j - 1];
    }
  }
  scanf("%I64d %I64d %I64d", &n, &m, &t);
  for (i = 4; i <= n; i++) {
    for (j = 1; (j <= m) && (t >= i + j); j++) {
      if (i + j == t) {
        r += pascal[i][n] * pascal[j][m];
      }
    }
  }
  printf("%I64d", r);
  return 0;
}
