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.util.*;
        import java.lang.*;
        import java.io.*;
        import java.math.BigDecimal;
     
        public class main{
        	public static BigDecimal f(BigDecimal n){
        		BigDecimal one = new BigDecimal(1);
        		if (n.compareTo(one) == -1){
                	return one;
        		}
            	return f(n.subtract(one)).multiply(n);
        	}
        	public static void main (String[] args) throws java.lang.Exception{
        		Scanner in = new Scanner(System.in);
        		BigDecimal d = new BigDecimal(0);
        		BigDecimal l = new BigDecimal(0);
        		BigDecimal n = new BigDecimal(in.nextInt()); 
        		BigDecimal m = new BigDecimal(in.nextInt());
        		BigDecimal t = new BigDecimal(in.nextInt());
        		BigDecimal i = n;
        		BigDecimal one = new BigDecimal(1);
        		BigDecimal four = new BigDecimal(4);
        		while(i.compareTo(four)  >= 0){
        			d = t.subtract(i);
        			if(d.compareTo(one) == -1 || d.compareTo(m) == 1){
        				i = i.subtract(one);
        				continue;
        			}
        			l = l.add((f(n).divide(f(i).multiply(f(n.subtract(i))))).multiply(f(m).divide(f(d).multiply(f(m.subtract(d))))));
        			i = i.subtract(one);
        	}
        	System.out.print(l);
        	}
        }