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 long long mod = 1000000007;
long long ncr(int n, int m) {
  long long res = 1;
  m = min(m, n - m);
  for (int i = 0; i < m; i++) {
    res = res * (n - i) / (i + 1);
  }
  return res;
}
map<long long, int> mp;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int x, y, z;
  cin >> x >> y >> z;
  long long res = 0;
  for (int w = 4; w <= x; w++) {
    for (int i = 1; i <= y; i++) {
      if (w + i != z || w > x || i > y)
        continue;
      else
        res += (ncr(x, w) * ncr((y), i));
    }
  }
  cout << res << endl;
  return 0;
}
