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 l[31][31] = {0};
void ncrvalue() {
  int i, j;
  l[0][0] = 1;
  for (i = 1; i <= 30; i++) {
    l[i][0] = 1;
    for (j = 1; j < i + 1; j++) l[i][j] = l[i - 1][j - 1] + l[i - 1][j];
  }
}
int main() {
  long long n, m, t, i, ans, j;
  cin >> n >> m >> t;
  ncrvalue();
  vector<long long> v;
  for (i = 4; i <= n; i++) {
    if (t - i >= 1 && t - i <= m) v.push_back(i);
  }
  ans = 0;
  for (i = 0; i < v.size(); i++) ans = ans + (l[n][v[i]] * l[m][t - v[i]]);
  cout << ans << endl;
}
