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 (r < 0 || r > n) return 0;
  long long res = 1, i = 0;
  while (i < r) ++i, res *= n - i + 1, res /= i;
  return res;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n, m, t, f, s;
  long long ans = 0;
  cin >> n >> m >> t;
  f = t - 1;
  s = 1;
  while (f >= 4 && s <= m) {
    ans += Com(n, f) * Com(m, s);
    f--;
    s++;
  }
  cout << ans;
}
