import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int m = sc.nextInt();
        boolean[][] keys = new boolean[n][m];
        for (int i = 0; i < n; i++) {
            char[] values = sc.next().toCharArray();
            for (int j = 0; j < m; j++) {
                keys[i][j] = values[j] == 'o';
            }
        }
        int max = 0;
        for (int i = 0; i < m; i++) {
            int count = 0;
            for (int j = 0; j < n; j++) {
                if (!keys[j][i]) {
                    count++;
                }
            }
            max = Math.max(max, count);
        }
        System.out.println(max + 1);
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}