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 int dp[35][35];
long long int comb(int N, int R) {
  if (R > N) return 0;
  if (N == R) return dp[N][R] = 1;
  if (R == 0) return dp[N][R] = 1;
  if (R == 1) return dp[N][R] = N;
  if (dp[N][R]) return dp[N][R];
  return dp[N][R] = comb(N - 1, R) + comb(N - 1, R - 1);
}
int main() {
  int N, M, T;
  long long int ans = 0;
  cin >> N >> M >> T;
  for (int i = 0; i + 4 < T; i++) {
    ans += comb(N, 4 + i) * comb(M, T - 4 - i);
  }
  cout << ans << endl;
  return 0;
}
