/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		int[] a1 = {1, 5, 3, 21};
		int[] b1 = {2, 10, 5, 1};

		System.out.println("max weight is"+maxWeight(a1,b1));

		int[] a2 = {10, 1, 1, 10};
		int[] b2 = {1, 1, 20, 1};
		System.out.println("max weight is "+maxWeight(a2,b2));
	}

	public static int maxWeight(int[] a, int[] b) {

		int n = a.length;
		if(n==0) return 0;
		if(n==1) return Math.max(a[0],b[0]);

		int dp[] = new int[n];

		dp[0] = Math.max(a[0], b[0]);
		dp[1] = Math.max(dp[0], Math.max(a[1], b[1]));

		for(int i=2;i<n;i++){
			int skip = dp[i-1];	
			int takeA = a[i] + dp[i-2];
			int takeB = b[i] + dp[i-2];

			dp[i] = Math.max(skip, Math.max(takeA, takeB));
		}

		return dp[n - 1];
 	}
}