fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();
    let grid = (0..n).map(|_| {
            let mut temp = String::new();
            std::io::stdin().read_line(&mut temp).ok();
            let temp = temp.trim();
            temp.chars().collect::<Vec<_>>()
        })
        .collect::<Vec<_>>();

    let mut result = 0usize;
    if !(0..n).any(|i| grid[0][i] == '#' || grid[n-1][i] == '#' || grid[i][0] == '#' || grid[i][n-1] == '#') {
        result = 4;
    }
    for dir in 0..2 {
        for is_w in 0..2 {
            let mut grid = grid.clone();
            let mut temp = 0usize;
            if is_w == 1 {
                for i in 0..n {
                    let cnt = (0..n).filter(|&j| grid[i][j] == '#').count();
                    if cnt > 1 { continue; }
                    if dir == 0 {
                        if cnt == 0 || grid[i][0] == '#' {
                            (1..n).for_each(|j| grid[i][j] = '#');
                            temp += 1;
                        } else if grid[i][n-1] == '#' {
                            (0..n-1).for_each(|j| grid[i][j] = '#');
                            temp += 1;
                        }
                    } else {
                        if cnt == 0 || grid[i][n-1] == '#' {
                            (0..n-1).for_each(|j| grid[i][j] = '#');
                            temp += 1;
                        } else if grid[i][0] == '#' {
                            (1..n).for_each(|j| grid[i][j] = '#');
                            temp += 1;
                        }
                    }
                }
                let j = if dir == 0 { 0 } else { n-1 };
                let cnt = (0..n).filter(|&i| grid[i][j] == '#').count();
                if cnt == 0 {
                    temp += 1;
                } else if cnt == 1 && (grid[0][j] == '#' || grid[n-1][j] == '#') {
                    temp += 1;
                }
            } else {
                for j in 0..n {
                    let cnt = (0..n).filter(|&i| grid[i][j] == '#').count();
                    if cnt > 1 { continue; }
                    if dir == 0 {
                        if cnt == 0 || grid[0][j] == '#' {
                            (1..n).for_each(|i| grid[i][j] = '#');
                            temp += 1;
                        } else if grid[n-1][j] == '#' {
                            (0..n-1).for_each(|i| grid[i][j] = '#');
                            temp += 1;
                        }
                    } else {
                        if cnt == 0 || grid[n-1][j] == '#' {
                            (0..n-1).for_each(|i| grid[i][j] = '#');
                            temp += 1;
                        } else if grid[0][j] == '#' {
                            (1..n).for_each(|i| grid[i][j] = '#');
                            temp += 1;
                        }
                    }
                }
                let i = if dir == 0 { 0 } else { n-1 };
                let cnt = (0..n).filter(|&j| grid[i][j] == '#').count();
                if cnt == 0 {
                    temp += 1;
                } else if cnt == 1 && (grid[i][0] == '#' || grid[i][n-1] == '#') {
                    temp += 1;
                }
            }
            result = result.max(temp);
        }
    }
    println!("{}", result);
}