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 C(long long n, long long k) {
  if (k > n) return 0;
  if (k == n) return 1;
  if (k == n - 1) return n;
  long long r = 1;
  for (long long d = 1; d <= k; ++d) {
    r *= n--;
    r /= d;
  }
  return r;
}
int main() {
  long long n, m, t, count = 0;
  cin >> n >> m >> t;
  for (int i = 4; (i) < (n + 1); ++(i))
    for (int j = 1; (j) < (m + 1); ++(j))
      if (j + i == t) count += C(n, i) * C(m, j);
  cout << count;
  return 0;
}
