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 sum;
long long C(int n, int r) {
  long long Res = 1;
  int memo[31] = {0};
  if (r > n) return 0;
  r = max(r, n - r);
  for (int i = n; i > r; i--) {
    Res *= i;
    for (int j = n - r; j > 1; j--)
      if (!memo[j] && Res % j == 0) Res /= j, memo[j] = 1;
  }
  return Res;
}
int main() {
  int n, m, t;
  cin >> n >> m >> t;
  for (int i = 4; i <= min(n, t - 1); i++) sum += C(n, i) * C(m, t - i);
  cout << sum << endl;
}
