#include <cstdio>
#include <cmath>
#include <cstring>
#include <ctime>
#include <iostream>
#include <algorithm>
#include <set>
#include <vector>
#include <sstream>
#include <queue>
#include <typeinfo>
#include <fstream>
typedef long long ll;
using namespace std;
//freopen("D.in","r",stdin);
//freopen("D.out","w",stdout);
#define sspeed ios_base::sync_with_stdio(0);cin.tie(0)
#define maxn 100
const int inf=0x7fffffff;   //无限大
ll n[maxn];
ll n2[maxn];
int N;
int main()
{
    int cas=1;
    int N;
    while(cin>>N)
    {
        if(N==0)
            break;
        for(int i=0;i<N;i++)
        {
            cin>>n[i];
            n2[i]=n[i];
        }
        ll ans=0;
        int flag=0;
        int kiss=0;
        for(int i=0;i<N;i++)
        {
            if(n[i]!=n[(i+1)%N])
            {
                kiss=0;
                break;
            }
            if(i==N-1)
                kiss=1;
        }
        while(kiss==0&&ans<=1000)
        {

            for(int i=0;i<N;i++)
            {
                n[i]=fabs(n2[i]-n2[(i+1)%N]);
            }
            for(int i=0;i<N;i++)
            {
                n2[i]=n[i];
            }
            ans++;
            for(int i=0;i<N;i++)
            {
                if(n[i]!=n[(i+1)%N])
                {
                    kiss=0;
                    break;
                }
                if(i==N-1)
                    kiss=1;
            }
        }
        if(kiss==1)
            printf("Case %d: %d iterations\n",cas,ans);
        else
            printf("Case %d: not attained\n",cas);
        cas++;
    }
    return 0;
}