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 cmemo[35][35];
long long choose(int n, int k) {
  long long& ans = cmemo[n][k];
  if (ans >= 0) return ans;
  if (k > n) return ans = 0;
  if (n == 0 && k == 0) return ans = 1;
  if (k == 0 || k == n) return ans = 1;
  return ans = choose(n - 1, k) + choose(n - 1, k - 1);
}
int main() {
  int N, M, T;
  cin >> N >> M >> T;
  for (int i = 0; i < 35; i++)
    for (int j = 0; j < 35; j++) cmemo[i][j] = -1;
  for (int i = 0; i < 35; i++)
    for (int j = 0; j < 35; j++) choose(i, j);
  long long ans = 0;
  for (int B = (4); B <= (N); B++) {
    int G = T - B;
    if (G < 1) continue;
    if (G > M) continue;
    ans += choose(N, B) * choose(M, G);
  }
  cout << ans << endl;
}
