fn main() {
    let mut nm = String::new();
    std::io::stdin().read_line(&mut nm).ok();
    let nm: Vec<usize> = nm.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let n = nm[0];
    let m = nm[1];
    let keys = (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 cnts = vec![n; m];
    for v in keys.iter() {
        for (i, &c) in v.iter().enumerate() {
            if c == 'o' {
                cnts[i] -= 1;
            }
        }
    }
    println!("{}", cnts.iter().max().unwrap() + 1);
}