#include<cstdio>

#include<cstring>

#include<iostream>

#include<algorithm>

using namespace std;

const int maxn = ;

const int HASH = ;

char s[maxn][];

int head[HASH],next[maxn];

int dp[maxn];

int n;

char temp[];   //变出来的字符串

int hash(char *s)

{

    int seed = ;

    int ret = ;

    while(*s)

    {

        ret = ret * seed + *(s++);

    }

    return (ret & 0x7fffffff ) % HASH ;

}

void input()

{

    n = ;

    memset(head,-,sizeof(head));

    while(scanf("%s",s[n]) == )

    {

        int id = hash(s[n]);

        next[n] = head[id];

        head[id] = n;

        n++;

    }

    n--;

}

int search()

{

    int i;

    int id = hash(temp);

    for(i=head[id]; i!=-; i=next[i])

    {

        if(strcmp(temp,s[i]) == )

            break;

    }

    return i;

}

void add(int cur,int loc,int addnum)

{

    int len = strlen(s[cur]);

    int i,j;

    for(i=,j=; i<loc; i++)

    {

        temp[j++] = s[cur][i];

    }

    temp[j++] = 'a' + addnum;

    for(; i<len; i++)

    {

        temp[j++] = s[cur][i];

    }

    temp[j] = '\0';

}

void del(int cur,int loc)

{

    int len = strlen(s[cur]);

    int i,j;

    for(i=,j=; i<loc; i++)

        temp[j++] = s[cur][i];

    i++;

    for(; i<len; i++)

        temp[j++] = s[cur][i];

    temp[j] = '\0';

}

void change(int cur,int loc,int addnum)

{

    strcpy(temp,s[cur]);

    temp[loc] += addnum;

}

int dfs(int cur)

{

    if(dp[cur] != -) return dp[cur];

    int len = strlen(s[cur]);

    int ret = ;

    //add;

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

    {

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

        {

            add(cur,i,j);

            int id = search();

            if(id!=- && strcmp(s[cur],temp) < )

            {

                ret = max(ret,dfs(id)+);

            }

        }

    }

    //del;

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

    {

        del(cur,i);

        int id = search();

        if(id != - && strcmp(s[cur],temp) < )

            ret = max(ret,dfs(id)+);

    }

    //change;

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

    {

        int lim = 'z' - s[cur][i];

        for(int j=; j<=lim; j++)

        {

            change(cur,i,j);

            int id = search();

            if(id != - && strcmp(s[cur],temp) < )

                ret = max(ret,dfs(id)+);

        }

    }

    dp[cur] = ret;

    return ret;

}

void solve()

{

    memset(dp,-,sizeof(dp));

    int ans = ;

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

    {

        ans = max(ans,dfs(i));

    }

    printf("%d\n",ans+);

}

int main()

{

   // freopen("E:\\acm\\input.txt","r",stdin);

    input();

    solve();

}