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 com(long long n, long long r) {
  if (n - r < r) r = n - r;
  long long i, j, s = 1;
  for (i = 0, j = 1; i < r; ++i) {
    s *= (n - i);
    for (; j <= r && s % j == 0; ++j) s /= j;
  }
  return s;
}
int main() {
  long long n, m, t, res = 0;
  cin >> n >> m >> t;
  for (int i = 4; t - i >= 1; i++)
    if (i > n || t - i > m)
      continue;
    else
      res += com(n, i) * com(m, (t - i));
  cout << res << endl;
  return 0;
}
