> #include<iostream>
> #include<cstring>
> #include<cstdio>
> using namespace std;
> int main()
> {
>     int n;
>     int map[27];
>     bool target[27][27];
>     char a[27];
>     while(cin>>n&&n!=0)
>     {
>         memset(target,false,sizeof(target));
>         memset(map,0,sizeof(map));
>         for(int i=1; i<=n; i++)
>         {
>             cin>>a;
>             for(int j=2; a[j]!='\0'; j++)
>             {
> 
>                 target[i][a[j]-'A'+1]=true;
>             }
>         }
>         int c[27]= {0};
>         for(int i=1; i<=n; i++)
>         {
>             memset(c,0,sizeof(c));
>             for(int j=1; j<=n; j++)
>             {
>                 if(target[i][j])
>                 {
>                     c[map[j]]=1;
>                 }
>             }
>             for(int j=1; j<=n; j++ )
>             {
>                 if(c[j]==0)
>                 {
>                     map[i]=j;
>                     break;
>                 }
>             }
>         }
>         int max=0;
>         for(int i=1; i<=n; i++)
>         {
>             if(map[i]>max)
>             {
>                 max=map[i];
>             }
>         }
>         if(max>1)
>         {
>             cout<<max<<" channels needed."<<endl;
>         }
>         else
>         {
>             cout<<max<<" channel needed."<<endl;
>         }
> 
>     }
>     return 0;
> }