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 mem[65][65];
long long cmb(long long n, long long k) {
  if (k > n) return 0;
  if (k == 0) return 1;
  if (mem[n][k]) return mem[n][k];
  long long ans = cmb(n - 1, k - 1) + cmb(n - 1, k);
  mem[n][k] = ans;
  return ans;
}
int main() {
  long long n, m, k;
  cin >> n >> m >> k;
  long long ans = 0;
  for (int i = 4; i <= k - 1; i++) {
    ans += cmb(n, i) * cmb(m, k - i);
  }
  cout << ans << "\n";
  return 0;
}
