use std::io::*;

fn main() {
    let mut s: String = String::new();
    std::io::stdin().read_to_string(&mut s).ok();
    let mut itr = s.trim().split_whitespace();
    let n: usize = itr.next().unwrap().parse().unwrap();
    let grid: Vec<Vec<char>> = (0..n)
        .map(|_| itr.next().unwrap().chars().collect())
        .collect();
    let mut m = Vec::new();
    for i in 0..n {
        for j in i + 1..n {
            if grid[i][j] == '-' {
                m.push((i, j));
            }
        }
    }

    let mut ans = 10;
    for bit in 0..(1 << m.len()) {
        let mut now = grid.clone();
        let mut point = Vec::new();
        for i in 0..m.len() {
            if bit >> i & 1 == 1 {
                now[m[i].0][m[i].1] = 'o';
                now[m[i].1][m[i].0] = 'x';
            }
        }

        for i in 0..n {
            let mut p = 0;
            for j in 0..n {
                if i != j {
                    if now[i][j] == 'o' {
                        p += 1;
                    }
                }
            }
            point.push((p, i));
        }
        point.sort_by(|a, b| b.0.cmp(&a.0));
        for i in 0..n {
            if point[i].1 == 0 {
                ans = std::cmp::min(ans, i + 1);
            }
        }
    }
    println!("{}", ans);
}