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;
unsigned long long Newton(unsigned long long n, unsigned long long k) {
  if (k == 0 || k == n)
    return 1;
  else {
    unsigned long long wyn = 1;
    if (k > n / 2) k = n - k;
    for (int j = 1; j <= k; ++j) wyn = wyn * (n - j + 1) / j;
    return wyn;
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  unsigned long long n, m, t;
  cin >> n >> m >> t;
  unsigned long long wyn = 0;
  for (int ch = 4; ch <= n; ++ch)
    if (t - ch <= m && t - ch > 0) wyn += Newton(n, ch) * Newton(m, t - ch);
  cout << wyn;
  return 0;
}
