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.* ;
public class Comb {
	static Long comb (int N , int C ){
	double res = 1;
	for (int i = 1; i <= C; i++) {
    res = res * (N - C + i) / i;}
   	return (long)res;
	}
public static void main (String args[]){
	Scanner sc = new Scanner(System.in); 
		int n = sc.nextInt(); 
		int m = sc.nextInt(); 
		int t = sc.nextInt();
		long sum = 0 ; 
			if (n+m == t )
				System.out.print (1); 
		else{
			if (t-m >= 4 ){
		for (int i = t-m ; i <= n & (t-i >= 1) ; i++){
				sum+= comb(n , i ) * comb(m , t-i );  
		}
			}
			else{
				for (int i = 4 ; i <= n & (t-i >= 1) ; i++){
				sum+= comb(n , i ) * comb(m,t-i );}
			}
				 
						  
		System.out.print(sum); }
}
} 
