#include <map>
#include <set>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <cctype>
#include <cstdio>
#include <limits>
#include <string>
#include <vector>
#include <cassert>
#include <climits>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iomanip>
#include <numeric>
#include <sstream>
#include <utility>
#include <iostream>
#include <algorithm>
#include <functional>

#define stop exit(0)
#define nc -1
#define eps 1e-10
#define inf 1000000000
#define mod 1000000007
#define mp make_pair

#define fill(array,value) memset(array,value,sizeof(array))
#define f(i,beg,end) for(int i=beg; i<=end; i++)
#define F(i,beg,end) for(int i=beg; i>=end; i--)
#define Max(a,b) ( (a>b)?a:b )
#define Min(a,b) ( (a<b)?a:b )
#define pi 3.1415926535897932384626433832
#define iread(var) scanf("%d",&var)
#define dread(var) scanf("%f",&var)
#define lread(var) scanf("%lld",&var)
#define input(name) freopen(name,"r",stdin)
#define output(name) freopen(name,"w",stdout)
typedef unsigned long long ull;
typedef unsigned int ui;
typedef long double ld;
typedef long long ll;

using namespace std;

string a[100100];
int n;

void init()
{
    cin >> n;
    cin.ignore();
    f(i,1,n)
        cin >> a[i];
}

bool ok(int currCount[10])
{
    bool isOk = true;
    f(i,0,9)
        if (!currCount[i]) isOk = false;
    return isOk;
}

void solve()
{
    int currCount[10]; fill(currCount,0);
    int fst, snd, maxLen = inf;

    fst = 1;
    f(i,0,a[1].size()-1)
        currCount[a[1][i]-'0']++;

    for(snd=2; snd<=n+1; snd++)
    {
        while (ok(currCount) && fst<=snd-1)
        {
//            if (maxLen > snd-fst+1)
//            {
//                cout << fst << " :: " << snd << endl;
//            }
            maxLen = Min(maxLen, snd-fst);
            f(i,0,a[fst].size()-1)
                currCount[ a[fst][i]-'0' ]--;
            fst++;
        }

        if (snd <= n)
        {
            f(i,0,a[snd].size()-1)
                currCount[a[snd][i]-'0']++;
        }

        while (ok(currCount) && fst<=snd)
        {
//            if (maxLen > snd-fst+1)
//            {
//                cout << fst << " :::: " << snd << endl;
//            }
            maxLen = Min(maxLen, snd-fst+1);
            f(i,0,a[fst].size()-1)
                currCount[ a[fst][i]-'0' ]--;
            fst++;
        }

    }

    if (maxLen != inf)
        cout << maxLen << endl;
    else
        cout << -1 << endl;
}

int main()
{
    cin.sync_with_stdio(false);
//	input("test.txt");

	input("numbers.in");
	output("numbers.out");

	int numberOfTests = 1;
//	cin >> numberOfTests;

	f(i,1,numberOfTests)
	{
		init();
		solve();
	}

	return 0;
}