#![allow(non_snake_case)]
#![allow(unused_imports)]
//use itertools::Itertools;
//use proconio::input;
//use proconio::marker::*;
use std::cmp::Reverse;
use std::collections::*;

fn main() {
    input! {
        n:usize,
        s:[chars;n],
    }

    let mut ans = n;
    let mut yet = vec![];
    let mut wins = vec![0; n];
    for i in 0..n {
        for j in i + 1..n {
            if s[i][j] == '-' {
                yet.push((i, j));
            } else if s[i][j] == 'o' {
                wins[i] += 1;
            } else {
                wins[j] += 1;
            }
        }
    }

    let m = yet.len();
    for i in 0..1 << m {
        let mut cnts = wins.clone();
        for j in 0..m {
            if i & (1 << j) != 0 {
                cnts[yet[j].0] += 1;
            } else {
                cnts[yet[j].1] += 1;
            }
        }

        let zero = cnts[0];
        cnts.sort();
        cnts.dedup();
        cnts.reverse();
        for (i, &cnt) in cnts.iter().enumerate() {
            if cnt == zero {
                ans = ans.min(i + 1);
            }
        }
    }

    println!("{}", ans);
}

mod input {
    #[macro_export]
    macro_rules! input {
        (source = $s:expr, $($r:tt)*) => {
            let mut iter = $s.split_whitespace();
            input_inner!{iter, $($r)*}
        };
        ($($r:tt)*) => {
            let s = {
                use std::io::Read;
                let mut s = String::new();
                std::io::stdin().read_to_string(&mut s).unwrap();
                s
            };
            let mut iter = s.split_whitespace();
            input_inner!{iter, $($r)*}
        };
    }

    #[macro_export]
    macro_rules! input_inner {
        ($iter:expr) => {};
        ($iter:expr, ) => {};

        ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
            let $var = read_value!($iter, $t);
            input_inner!{$iter $($r)*}
        };
    }

    #[macro_export]
    macro_rules! read_value {
        ($iter:expr, ( $($t:tt),* )) => {
            ( $(read_value!($iter, $t)),* )
        };

        ($iter:expr, [ $t:tt ; $len:expr ]) => {
            (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
        };

        ($iter:expr, chars) => {
            read_value!($iter, String).chars().collect::<Vec<char>>()
        };

        ($iter:expr, usize1) => {
            read_value!($iter, usize) - 1
        };

        ($iter:expr, $t:ty) => {
            $iter.next().unwrap().parse::<$t>().expect("Parse error")
        };
    }
}