/*

zju 1084 Channel Allocation

00:00.00 440k

2004.09.11 by adai

*/

#include <iostream>

#include <cstring>

using namespace std;

#ifdef WIN32

#define for if(0); else for

#endif

int mat[26][26];

int n, color, found;

int mm[26];

int check(int nn) {

for (int i = 0; i < nn; i ++) {

if (mat[i][nn] && mm[i] == mm[nn]) return 0;

}

return 1;

}

int dfs(int nn) {

if (nn == n) {

found = 1;

return 0;

}

if (found) return 0;

for (int i = 1; i <= color; i ++) {

mm[nn] = i;

if (check(nn)) dfs(nn + 1);

}

return 0;

}

int main() {

while (cin >> n && n) {

memset(mat, 0, sizeof(mat));

for (int i = 0; i < n; i ++) {

char tt[28];

cin >> tt;

int ss = tt[0] - 'A';

for (int j = 2; tt[j] != '\0'; j ++) mat[ss][tt[j] - 'A'] = mat[tt[j] - 'A'][ss] = 1;

}

found = 0;

for (color = 1; color <= 4; color ++) {

mm[0] = 1;

dfs(1);

if (found) break;

}

if (color == 1) cout << "1 channel needed." << endl;

else cout << color << " channels needed." << endl;

}

return 0;

}