use proconio::input;

const NUM_STATES: usize = 5;

fn main() {
    input! {
        n: usize,
        aa: [usize; n],
        bb: [usize; n],
        cc: [usize; n],
    }

    let mut dp1 = vec![[0_usize; NUM_STATES]; n + 1];
    for i in 0..n {
        let weights = [aa[i], bb[i], cc[i], bb[i], aa[i]];
        for state in 0..NUM_STATES {
            for next_state in state..NUM_STATES {
                dp1[i + 1][next_state] =
                    dp1[i + 1][next_state].max(dp1[i][state] + weights[next_state]);
            }
        }
    }

    let mut dp2 = vec![[0_usize; NUM_STATES]; n + 1];
    for i in 0..n {
        let weights = [aa[i], bb[i], aa[i], bb[i], aa[i]];
        for state in 0..NUM_STATES {
            for next_state in state..NUM_STATES {
                dp2[i + 1][next_state] =
                    dp2[i + 1][next_state].max(dp2[i][state] + weights[next_state]);
            }
        }
    }

    let ans = dp1[n][2..].iter().chain(&dp2[n][3..]).max().unwrap();
    println!("{}", ans);
}