import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int a=sc.nextInt(),b=sc.nextInt();
		int shorter=0,longer=0;
		if(a>b){
			shorter=b;
			longer=a;
		}else{
			shorter=a;
			longer=b;
		}
		int i=0;
		while(shorter>=0){
			if(i%2==0)shorter--;
			else longer--;
			i++;
		}
		System.out.println(i-1);
		sc.close();
		return;
	}
}