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 comb(long long a, long long b) {
  long long res = 1LL;
  if (b > a) return 0LL;
  int k = min(b, a - b);
  for (long long i = a; i > max(a - b, b); i--) {
    res *= i;
    if (res % k == 0 && k >= 1) {
      res /= 1LL * k;
      k--;
    }
  }
  for (long long i = k; i >= 1; i--) {
    res /= i;
  }
  return res;
}
int main() {
  long long m, n, t;
  cin >> n >> m >> t;
  long long tot = 0LL;
  for (long long i = 4LL; i < t; i++) {
    tot += comb(n, i) * comb(m, t - i);
  }
  cout << tot << endl;
}
