import java.util.*;
import java.io.*;
public class Main{
public static void main(String[] args) {
int[] A = {10,20,00};
int[] B = {-10,50,20};
int C = 20;
System.out.println(solve(A,B,C));
}
private static int solve(int[] A,int[] B,int C){
int len = A.length;
int[] dp1 = new int[len];
int[] dp2 = new int[len];
dp1[len-1] = A[len-1];
dp2[len-1] = B[len-1];
int max = Math.max(dp1[len-1],dp2[len-1]);
for(int i=A.length-2;i >= 0;--i){
dp1[i] = Math.max(A[i] + dp1[i+1],A[i] + dp2[i+1] - C);
dp2[i] = Math.max(B[i] + dp2[i+1],B[i] + dp1[i+1] - C);
max = Math.max(dp1[i],dp2[i]);
}
return max;
}
}
