> #include <iostream>
> #include <algorithm>
> using namespace std;
> char a[27][27];
> int b[26];
> 
> int main()
> {
> 	//freopen("in.txt","r",stdin);
> 	int n,i,j,p,q,min;
> 	while(scanf("%d",&n)&&n!=0)
> 	{
> 		memset(a,0,sizeof(a));
> 		for(i=0;i<n;i++)
> 			scanf("%s",a[i]);
> 		for(i=0;i<26;i++)
> 			b[i]=1;
> 		for(i=0;i<n;i++)
> 		{
> 			for(j=2;j<=n&&a[i][j]!=0;j++)
> 			{
> 				p=a[i][j]-65;
> 				q=a[0][j]-65;
> 				if(a[i][j]<a[i][0])
> 					continue;
> 				if(b[p]==b[q])
> 					b[p]++;
> 			}
> 		}
> 
> 		min=*max_element(b,b+sizeof(b)/sizeof(b[0]));
> 		if(min==1)
> 			printf("%d channel needed.\n",min);
> 		else
> 			printf("%d channels needed.\n",min);
> 	}
> 	return 0;
> }