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;
const int MAX = (1 << 15) + 100;
const int inf = 522133279;
long long C(int n, int m) {
  long long fenzi = 1;
  int fenmu = 1;
  for (int i = n - m + 1; i <= n; i++) {
    fenzi *= i;
    fenzi /= fenmu++;
  }
  return fenzi;
}
int main() {
  int m, n, t;
  cin >> m >> n >> t;
  long long ans = 0;
  for (int i = 1; i <= t - 4; i++) {
    if (i <= n && t - i <= m) ans += C(m, t - i) * C(n, i);
  }
  cout << ans << endl;
  return 0;
}
