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;
int n, m, t;
unsigned long long res;
unsigned long long combinari(int n, int k) {
  unsigned long long rez = n, i;
  if (k > n) return 0;
  if (n == k) return 1;
  if (k > (n - k)) k = n - k;
  for (i = n - 1; i > n - k; i--) {
    rez = rez * i;
    rez = rez / (n - i + 1);
  }
  return rez;
}
int main() {
  cin >> n >> m >> t;
  for (int b = 4; b <= t - 1; b++) {
    res = res + combinari(n, b) * combinari(m, t - b);
  }
  cout << res;
  return 0;
}
