search1129

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;

bool map[30][30];
int cmpmax(int a,int b)
{
	return a>b;
}

int main()
{
	char str[33];
	int i,j,num,color_number;
	int color[33];

	while(scanf("%d",&num),num)
	{
		memset(map,0,sizeof(map));
		memset(color,0,sizeof(color));
		color_number=1;
		

		for(i=1;i<=num;i++)
		{
			scanf("%s",str);
			for(j=2;j<=strlen(str)-1;j++)
				map[i][str[j]-‘A‘+1]=1;
		}
		
		color[1]=1;
	    int	cur_color=1;
		bool ok;
		for(i=2;i<=num;i++)
		{
			cur_color=1;//对每个节点从第一个颜色开始试，直至成功

			ok=0;
			while(!ok)
			{
				color[i]=cur_color++;
				
				for(j=1;j<=num;j++)
				{
					if(map[i][j]==1 && color[i]==color[j])
						break;
				}

				if(j==num+1)
					ok=1;
			}
		}

		sort(color+1,color+30,cmpmax);
		if (color[1] == 1)
            printf("1 channel needed.\n");
        else
            printf("%d channels needed.\n", color[1]);
	}
	return 1;
}