#include <bits/stdc++.h>

 const int maxn = 5e5 + ;

 /* AUTOMATON */

 int last;

 int tail;

 int mini[maxn];

 int maxi[maxn];

 int step[maxn];

 int fail[maxn];

 int next[maxn][];

 inline void buildAutomaton(char *s)

 {

     last = ;

     tail = ;

     while (*s)

     {

         int c = *s++ - 'a';

         int p = last;

         int t = tail++;

         step[t] = step[p] + ;

         mini[t] = maxi[t] = step[t];

         while (p && !next[p][c])

             next[p][c] = t, p = fail[p];

         if (p)

         {

             int q = next[p][c];

             if (step[q] == step[p] + )

                 fail[t] = q;

             else

             {

                 int k = tail++;

                 fail[k] = fail[q];

                 fail[q] = fail[t] = k;

                 step[k] = step[p] + ;

                 mini[k] = maxi[k] = step[k];

                 for (int i = ; i < ; ++i)

                     next[k][i] = next[q][i];

                 while (p && next[p][c] == q)

                     next[p][c] = k, p = fail[p];

             }

         }

         else

             fail[t] = ;

         last = t;

     }

 }

 inline void searchAutomaton(char *s)

 {

     memset(maxi, , sizeof(maxi));

     for (int t = , k = ; *s; )

     {

         int c = *s++ - 'a';

         if (next[t][c])

             ++k, t = next[t][c];

         else

         {

             while (t && !next[t][c])

                 t = fail[t];

             if (t)

                 k = step[t] + , t = next[t][c];

             else

                 k = , t = ;

         }

         if (maxi[t] < k)

             maxi[t] = k;

     }

     for (int i = tail - ; i; --i)

         if (maxi[fail[i]] < maxi[i])

             maxi[fail[i]] = maxi[i];

     for (int i = ; i < tail; ++i)

         if (mini[i] > maxi[i])

             mini[i] = maxi[i];

 }

 inline int calculateAutomaton(void)

 {

     register int ret = ;

     for (int i = ; i < tail; ++i)

         if (ret < mini[i])

             ret = mini[i];

     return ret;

 }

 /* MAIN FUNC */

 char str[maxn];

 signed main(void)

 {

     int n;

     scanf("%d", &n);

     scanf("%s", str);

     buildAutomaton(str);

     for (int i = ; i < n; ++i)

         scanf("%s", str), searchAutomaton(str);

     printf("%d\n", calculateAutomaton());

 }