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;
const int N = 5e+5 + 5;
const long long inf = 4e+18;
const long long mod = 1e+9 + 7;
inline void boost() {
  ios_base ::sync_with_stdio(NULL);
  cin.tie(NULL), cout.tie(NULL);
}
long long c[100][100];
int main() {
  boost();
  long long n, m, k;
  cin >> n >> m >> k;
  long long ans = 0;
  for (int i = 0; i <= 30; i++) {
    c[i][0] = 1;
    c[i][i] = 1;
    for (int j = 1; j < i; j++) {
      c[i][j] = c[i - 1][j - 1] + c[i - 1][j];
    }
  }
  int first = 4;
  while (first < k && first <= n) {
    int second = k - first;
    if (m < second) {
      first++;
      continue;
    }
    ans += c[n][first] * c[m][second];
    first++;
  }
  cout << ans;
}
