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 a[50][50], b[50][50];
int main() {
  int n, m, t, i, j;
  long long ans;
  cin >> n >> m >> t;
  memset(a, 0, sizeof(a));
  memset(b, 0, sizeof(b));
  for (i = 0; i <= n; i++) a[i][0] = a[i][i] = 1;
  for (i = 0; i <= m; i++) b[i][0] = b[i][i] = 1;
  for (i = 1; i <= n; i++)
    for (j = 1; j < i; j++) a[i][j] = a[i - 1][j] + a[i - 1][j - 1];
  for (i = 1; i <= m; i++)
    for (j = 1; j < i; j++) b[i][j] = b[i - 1][j] + b[i - 1][j - 1];
  ans = 0;
  for (i = 4; i <= n; i++)
    for (j = 1; j <= m; j++)
      if (i + j == t) ans += a[n][i] * b[m][j];
  cout << ans << endl;
  return 0;
}
