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 nCr(long long n, long long r) {
  if (r == 0) return 1;
  if (r > n / 2) return nCr(n, n - r);
  long long res = 1;
  for (long long k = 1; k <= r; ++k) {
    res *= n - k + 1;
    res /= k;
  }
  return res;
}
int main() {
  long long n, m, Sum = 0, t, n1, n2;
  cin >> n >> m >> t;
  for (int b = 4; b <= n; b++) {
    if (t - b > 0 && t - b <= m) {
      n1 = nCr(n, b);
      n2 = nCr(m, t - b);
      Sum += (n1 * n2);
    }
  }
  cout << Sum;
}
