#include<iostream>
#include<vector>
//#include"grader.cpp"
using namespace std;
using ll = long long;

int tempo_massimo(int N, int a[], int b[]) {
    vector<vector<int>> dp(N, vector<int>(3, 0));
    dp[0][0] = 0; dp[0][1] = a[0]; dp[0][2] = b[0];

    for(int i = 1; i < N; i++) {
        dp[i][0] = max(dp[i-1][1], dp[i-1][2]);
        dp[i][1] = max(dp[i-1][1], dp[i-1][2]) + a[i];
        dp[i][2] = dp[i-1][0] + b[i];        
    }

    return max(dp[N-1][1], dp[N-1][2]);
}