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.io.StreamTokenizer;

public class codeforcesB {
    static StreamTokenizer st;
    public static void main(String[] args) throws  IOException{
        st = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
    	int n = nextInt();
        int m = nextInt();
        int t = nextInt();
        long ans = 0;
        for (int i=4;i<=n;i++) 
        	for (int j=1;j<=m;j++) {
        		if (i+j==t) ans+=(combination(i,n)*combination(j,m));
        	}
        System.out.println(ans);
    }
    private static long combination(int q,int w) {
    	long sum = 1;
    	for (int i=q+1;i<=w;i++){
    		sum*=i; 
    		sum/=(i-q);
    	}
		return sum;
    }
    private static int nextInt() throws IOException{
        st.nextToken();
        return (int) st.nval;
    }
}