use proconio::input;

fn main() {
    input! {
        n:usize,
        a:[[usize;3];n],
    }

    let mut dp = vec![[(0, 0); 3]; n];
    for i in 0..3 {
        dp[0][i] = (a[0][i], a[0][i].saturating_sub(1));
    }

    for i in 1..n {
        for j in 0..3 {
            for k in 0..3 {
                if j == k {
                    continue;
                }
                if dp[i][k].0 < dp[i - 1][j].0 + dp[i - 1][j].1 + a[i][k] {
                    dp[i][k].0 = dp[i - 1][j].0 + dp[i - 1][j].1 + a[i][k];
                    dp[i][k].1 = (dp[i - 1][j].1 + a[i][k]).saturating_sub(1);
                }
            }
        }
    }

    let ans = dp[n - 1][0].0.max(dp[n - 1][1].0).max(dp[n - 1][2].0);
    println!("{}", ans);
}