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>
int64_t choose(int n, int k) {
  int64_t r = 1;
  if (k + k > n) {
    k = n - k;
  }
  for (int i = 1; i <= n - k; ++i) {
    r *= k + i;
    r /= i;
  }
  return r;
}
int main() {
  int n, m, t;
  std::cin >> n >> m >> t;
  int64_t solution = 0;
  for (int i = 4; i <= n; ++i) {
    if (i + 1 <= t && t - i <= m) {
      solution += choose(n, i) * choose(m, t - i);
    }
  }
  std::cout << solution << '\n';
}
