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
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;
 
public class Main {
    public static int N, M, T;
   // public static long[][] C = new long[35][35];
    public static long Result;
    public static void main(String[] args) throws IOException {
      Scanner Input = new Scanner(System.in);
          Result = 0;
          N = Input.nextInt();
          M = Input.nextInt();
          T = Input.nextInt();
          for(int i = 1; i < T; i++) {
              if(T - i < 4) break;
              if(i > M)     break;
              Result += (long) PreCa(M, i) * (PreCa(N, T - i));
          }
          System.out.println(Result);
    }
    
    public static long PreCa(int First, int Second) {
        long[][] C = new long[100][100];
        for(int i = 0; i < 31; i++)    
            C[i][0] = C[0][i] = 1;
        for(int i = 1; i < 31; i++) {
            for(int j = 1; j <= i; j++) {
                C[i][j] = (i != j) ? C[i - 1][j] + C[i - 1][j - 1] : 1;
            }
        }
        return C[First][Second];
    }
 
}