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 nCi(long long n, long long r) {
  double prod = 1;
  for (int i = 1; i <= r; i++) {
    prod = (prod * (n - (long long)i + 1) / (long long)i);
  }
  return (long long)prod;
}
int main() {
  int n, m, t;
  cin >> n >> m >> t;
  long long sum = 0;
  for (int i = 4; i <= t - 1; i++) {
    int j = t - i;
    {
      if (i <= n and j <= m) {
        sum += nCi(n, min(i, n - i)) * nCi(m, min(j, m - j));
      }
    }
  }
  cout << sum;
  return 0;
}
