//

 //by coolxxx

 ////<bits/stdc++.h>

 #include<iostream>

 #include<algorithm>

 #include<string>

 #include<iomanip>

 #include<map>

 #include<memory.h>

 #include<time.h>

 #include<stdio.h>

 #include<stdlib.h>

 #include<string.h>

 //#include<stdbool.h>

 #include<math.h>

 #define min(a,b) ((a)<(b)?(a):(b))

 #define max(a,b) ((a)>(b)?(a):(b))

 #define abs(a) ((a)>0?(a):(-(a)))

 #define lowbit(a) (a&(-a))

 #define sqr(a) ((a)*(a))

 #define swap(a,b) ((a)^=(b),(b)^=(a),(a)^=(b))

 #define mem(a,b) memset(a,b,sizeof(a))

 #define eps (1e-8)

 #define J 10

 #define MAX 0x7f7f7f7f

 #define PI 3.14159265358979323

 #define N 2004

 #define M 76

 using namespace std;

 typedef long long LL;

 int cas,cass;

 int n,m,lll,ans;

 int q[N];

 string s[N];

 void work()

 {

     int i,l,r,mid;

     lll=;

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

     {

         for(l=,r=lll;l<r;)

         {

             mid=(l+r+)>>;

             if(s[i].find(s[q[mid]])==)l=mid;

             else r=mid-;

         }

         q[r+]=i;

         lll=max(lll,r+);

     }

 }

 int main()

 {

     #ifndef ONLINE_JUDGE

 //    freopen("1.txt","r",stdin);

 //    freopen("2.txt","w",stdout);

     #endif

     int i,j;

 //    for(scanf("%d",&cas);cas;cas--)

 //    for(scanf("%d",&cas),cass=1;cass<=cas;cass++)

 //    while(~scanf("%s",s))

     while(~scanf("%d",&n))

     {

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

         {

             cin>>s[i];

         }

         work();

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

     }

     return ;

 }

 /*

 //

 //

 */