#include<cstdio>

#include<iostream>

#include<algorithm>

#include<cstring>

#include<string>

#include<queue>

using namespace std;

struct Node

{

    string s;

    int mod;

    Node(string s="",int mod=): s(s),mod(mod) {}

};

bool can[];

bool vis[];

string ans;

bool bfs(int n)

{

    queue<Node> Q;

    string temp = "";

    Q.push(Node(temp,));

    while(!Q.empty())

    {

        Node node = Q.front();

        Q.pop();

        if(node.mod ==  && node.s != "" && node.s!="")

        {

            ans = node.s;

            return true;

        }

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

        {

            if(!can[i] ) continue;

            if(i ==  && node.s == "") continue;

            int mod = (node.mod* + i)%n;

            if(vis[mod]) continue;

            temp = node.s + char(i + '');

            vis[mod] = true;

            Q.push(Node(temp,mod));

        }

    }

    return false;

}

int main()

{

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

    int n,m;

    int T = ;

    while(cin>>n>>m)

    {

        for(int i=; i<=; i++) can[i] = true;

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

        {

            int a;

            scanf("%d",&a);

            can[a] = false;

        }

        ans = "";

        memset(vis,,sizeof(vis));

        printf("Case %d: ",++T);

        if(!bfs(n))

            printf("-1\n");

        else

            cout<<ans<<endl;

    }

}