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[31][31];
int main() {
  c[0][0] = 1;
  for (int i = 1; i < 31; ++i) c[0][i] = 0;
  for (int i = 1; i < 31; ++i) {
    for (int j = 0; j < 31; ++j) {
      if (j == 0)
        c[i][j] = 1;
      else
        c[i][j] = c[i - 1][j - 1] + c[i - 1][j];
    }
  }
  long long n, m, t;
  cin >> n >> m >> t;
  long long count = 0;
  for (int b = max(4LL, t - m); b <= min(t - 1, n); ++b) {
    count += c[n][b] * c[m][t - b];
  }
  cout << count << endl;
}
