using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static string[] SList(long n) => Enumerable.Repeat(0, (int)n).Select(_ => ReadLine()).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, m) = (c[0], c[1]);
        var s = SList(n);
        var pt = 0;
        for (var i = 0; i < m; ++i)
        {
            if (s[0][i] != s[1][i])
            {
                pt = i;
                break;
            }
        }
        var ans = 0;
        var t1 = s[0].ToList();
        t1.Insert(pt, s[1][pt]);
        var flg = true;
        foreach (var si in s)
        {
            if (!Check(t1, si))
            {
                flg = false;
                break;
            }
        }
        if (flg) ++ans;
        var t2 = s[1].ToList();
        t2.Insert(pt, s[0][pt]);
        flg = true;
        foreach (var si in s)
        {
            if (!Check(t2, si))
            {
                flg = false;
                break;
            }
        }
        if (flg) ++ans;
        WriteLine(ans);
    }
    static bool Check(List<char> t, string s)
    {
        var pos = 0;
        for (var i = 0; i < t.Count; ++i)
        {
            if (pos < s.Length && t[i] == s[pos]) ++pos;
        }
        return pos == s.Length;
    }
}