> #include<iostream>
> #include<string>
> #include<string.h>
> using namespace std;
> 
> int main() {
> 	int n;
> 	string in[30];
> 	int color[30];
> 	while (cin >> n&&n) {
> 		//get
> 		for (int i = 0; i < n; i++) {
> 			color[i] = 1;
> 		}
> 		for (int i = 0; i < n; i++) {
> 			cin >> in[i];
> 		}
> 		//sort
> 		for (int i = 0; i < n - 1; i++) {
> 			for (int j = i + 1; j < n; j++) {
> 				if (in[i].length() < in[j].length()) {
> 					string t;t = in[i];in[i] = in[j];in[j] = t;
> 				}
> 			}
> 		}
> 		//color
> 		int ans = 1;
> 		for (int i = 0; i < n; i++) {
> 			int x = in[i][0] - 'A';
> 			for (int j = 2; j < in[i].length(); j++) {
> 				if (color[in[i][j] - 'A'] == color[x])
> 				{
> 					color[in[i][j] - 'A'] = color[x] + 1;
> 					if (ans < color[x] + 1)ans = color[x] + 1;
> 				}
> 			}
> 		}
> 		if(ans==1)
> 		cout << ans <<" channel needed." <<endl;
> 		else {
> 			cout << ans << " channels needed." << endl;
> 		}
> 	}
> }