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 N, long long R) {
  long long L, sum = 1, i = 1;
  if (R > N / 2)
    L = N - R;
  else {
    L = R;
  }
  while (L--) {
    sum *= N--;
    sum /= i++;
  }
  return sum;
}
int main() {
  long long n, m, t, ans = 0;
  cin >> n >> m >> t;
  for (int i = 4; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      long long o = i + j;
      if (o == t) {
        ans += COMB(n, i) * COMB(m, j);
      }
    }
  }
  cout << ans;
  return 0;
}
