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>
long long int mat[100][100] = {};
long long int comb(int n, int r) {
  if (r == 0 || n == r) return 1;
  if (n < r) return 0;
  long long int ans = 0;
  if (mat[n - 1][r - 1] != 0)
    ans += mat[n - 1][r - 1];
  else {
    mat[n - 1][r - 1] = comb(n - 1, r - 1);
    ans += mat[n - 1][r - 1];
  }
  if (mat[n - 1][r] != 0)
    ans += mat[n - 1][r];
  else {
    mat[n - 1][r] = comb(n - 1, r);
    ans += mat[n - 1][r];
  }
  return ans;
}
int main() {
  int n, m, t, j;
  scanf("%d%d%d", &n, &m, &t);
  j = t - 4;
  long long ans = 0;
  for (int i = 4; i <= n && j >= 1; i++, j--) {
    ans += comb(n, i) * comb(m, j);
  }
  printf("%lld", ans);
  return 0;
}
