#include<bits/stdc++.h>

#define LL long long

#define fi first

#define se second

#define mk make_pair

#define PII pair<int, int>

using namespace std;

const int N = 2e5 + ;

const int inf = 0x3f3f3f3f;

const LL INF = 0x3f3f3f3f3f3f3f3f;

const int mod = 1e9 + ;

int n, m, tot, vis[N], from[N], who[N], ans[N];

bool is[];

void init() {

    tot = ;

    memset(vis, , sizeof(vis));

    memset(is, , sizeof(is));

}

int main() {

    int cas = ;

    while(scanf("%d%d", &n, &m) != EOF) {

        init();

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

            int x; scanf("%d", &x);

            is[x] = true;

        }

        queue<int> que;

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

            if(is[i]) continue;

            if(i%n==) {

                ans[tot++] = i;

                break;

            }

            vis[i%n] = ;

            from[i%n] = ;

            who[i%n] = i;

            que.push(i%n);

        }

        if(!tot) {

            while(!que.empty() && !tot) {

                int u = que.front(); que.pop();

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

                    if(is[i]) continue;

                    int v = (u*+i)%n;

                    if(!v) {

                        ans[tot++] = i;

                        while(u) {

                            ans[tot++] = who[u];

                            u = from[u];

                        }

                        reverse(ans, ans + tot);

                        break;

                    }

                    if(vis[v]) continue;

                    vis[v] = vis[u] + ;

                    from[v] = u;

                    who[v] = i;

                    que.push(v);

                }

            }

        }

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

        if(!tot) puts("-1");

        else {

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

                printf("%d", ans[i]);

            puts("");

        }

    }

    return ;

}

/*

*/