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 v[35][35];
long long C(int n, int k) {
  if (v[n][k]) return v[n][k];
  if (k == 0) return 1;
  if (n == k) return 1;
  v[n][k] = C(n - 1, k) + C(n - 1, k - 1);
  return v[n][k];
}
int main() {
  long long n, m, t, i, rez = 0;
  cin >> n >> m >> t;
  for (i = max(4LL, t - m); i <= min(n, t - 1); ++i)
    rez += C(n, i) * C(m, t - i);
  cout << rez;
  return 0;
}
