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 M[61][61];
long long dp(int n, int k) {
  if (k > n) return 0;
  if (k == n or k == 0) return 1;
  if (M[n][k] == -1) M[n][k] = dp(n - 1, k) + dp(n - 1, k - 1);
  return M[n][k];
}
int main() {
  long long n, m, t;
  cin >> n >> m >> t;
  long long res = 0;
  memset(M, -1, sizeof(M));
  for (int i = 4; i <= min(t - 1, n); ++i) res += dp(n, i) * dp(m, t - i);
  cout << res << endl;
}
