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 C(int n, int m) {
  long long z = 1;
  for (int i = 0; i < m; ++i) z = z * (n - i) / (i + 1);
  return z;
}
int main() {
  long long n, m, p;
  cin >> n >> m >> p;
  cout << C(n + m, p) - C(n, p) - C(m, p) - C(n, 1) * C(m, p - 1) -
              C(n, 2) * C(m, p - 2) - C(n, 3) * C(m, p - 3);
  return 0;
}
