#include <iostream>#include <cstring>using namespace std;const int MAX = 12;class Tower {public: double x, y; void set() { cin >> x >> y; } bool near(const Tower& t) const { return ((x - t.x) * (x - t.x) + (y - t.y) * (y - t.y)) <= 20 * 20; }};int n, no = 0, color[MAX];bool map[MAX][MAX];Tower tower[MAX];void init() { memset(map, false, sizeof(map));}bool check(int v) { for (int i = 0; i < n; i++) { if (map[v][i] && color[v] == color[i]) { return false; } } return true;}bool DFS(int v, int c) { if (c == 4 || v >= n) { return true; } for (int i = 1; i <= c; i++) { color[v] = i; if (check(v)) { if (DFS(v + 1, c)) { return true; } } color[v] = 0; } return false;}int main() { while (cin >> n && n) { init(); for (int i = 0; i < n; i++) { tower[i].set(); } for (int i = 0; i < n - 1; i++) { for (int j = i + 1; j < n; j++) { if (tower[i].near(tower[j])) { map[i][j] = map[j][i] = true; } } } for (int i = 1; i <= 4; i++) { memset(color, 0, sizeof(color)); if (DFS(0, i)) { cout << "The towers in case " << ++no << " can be covered in " << i << " frequencies." << endl; break; } } } return 0;}
