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 C[35][35];
  C[0][0] = 1;
  int k, n;
  for (n = 1; n <= 30; n++) {
    C[0][n] = 1;
    C[n][n] = 1;
    for (k = 1; k < n; k++) C[k][n] = C[k - 1][n - 1] + C[k][n - 1];
  }
  int m, t, i;
  scanf("%d %d %d", &m, &n, &t);
  long long res = 0;
  for (i = 4; i <= t - 1; i++) {
    if (i > m) break;
    if (t - i > n) continue;
    res += C[i][m] * C[t - i][n];
  }
  printf("%I64d", res);
}
