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;
vector<vector<int> > AdjList;
long long int c[65][65];
void ini() {
  c[0][0] = c[1][0] = c[1][1] = 1;
  for (int i = 2; i < 65; i++) {
    c[i][0] = 1;
    int j;
    for (j = 1; j < i; j++) {
      c[i][j] = c[i - 1][j - 1] + c[i - 1][j];
    }
    c[i][j] = 1;
  }
}
int main() {
  ini();
  long long int out = 0;
  int n, m, k;
  cin >> n >> m >> k;
  for (int i = 0; i <= k; i++) {
    int boy = i;
    int girl = k - i;
    if (boy <= n && girl <= m && boy >= 4 && girl >= 1) {
      out += c[n][boy] * c[m][girl];
    }
  }
  cout << out << endl;
  return 0;
}
