#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <iterator>
#include <complex>
#include <queue>
#include <stack>
#include <cmath>
using namespace std;
typedef long long LL;

class CDPlayer
{
public:
	int isRandom(vector <string> songlist, int n)
	{
		string s;
		for(int i=0; i<songlist.size(); ++i)
			s += songlist[i];

		for(int k=0; k<n; ++k)
			if( check(s, k, n) )
				return k;
		return -1;
	}

	bool check(const string& s, int k, int n)
	{
		for(int i=0,e=k; i<s.size(); i=e,e+=n)
			if( !distinct(s, i, min<int>(e,s.size())) )
				return false;
		return true;
	}

	bool distinct( const string& s, int i, int e )
	{
		set<char> x;
		for(; i<e; ++i)
			if( x.count(s[i]) )
				return false;
			else
				x.insert( s[i] );
		return true;
	}


// BEGIN CUT HERE
	public:
	void run_test(int Case) { if ((Case == -1) || (Case == 0)) test_case_0(); if ((Case == -1) || (Case == 1)) test_case_1(); if ((Case == -1) || (Case == 2)) test_case_2(); if ((Case == -1) || (Case == 3)) test_case_3(); if ((Case == -1) || (Case == 4)) test_case_4(); if ((Case == -1) || (Case == 5)) test_case_5(); if ((Case == -1) || (Case == 6)) test_case_6(); }
	private:
	template <typename T> string print_array(const vector<T> &V) { ostringstream os; os << "{ "; for (typename vector<T>::const_iterator iter = V.begin(); iter != V.end(); ++iter) os << '\"' << *iter << "\","; os << " }"; return os.str(); }
	void verify_case(int Case, const int &Expected, const int &Received) { cerr << "Test Case #" << Case << "..."; if (Expected == Received) cerr << "PASSED" << endl; else { cerr << "FAILED" << endl; cerr << "\tExpected: \"" << Expected << '\"' << endl; cerr << "\tReceived: \"" << Received << '\"' << endl; } }
	void test_case_0() { string Arr0[] = {"BBAC"}; vector <string> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[0]))); int Arg1 = 3; int Arg2 = 1; verify_case(0, Arg2, isRandom(Arg0, Arg1)); }
	void test_case_1() { string Arr0[] = {"BACAB",
 "BCA"}; vector <string> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[0]))); int Arg1 = 3; int Arg2 = 2; verify_case(1, Arg2, isRandom(Arg0, Arg1)); }
	void test_case_2() { string Arr0[] = {"AAACBACBACBACBACBACBACB"}; vector <string> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[0]))); int Arg1 = 3; int Arg2 = -1; verify_case(2, Arg2, isRandom(Arg0, Arg1)); }
	void test_case_3() { string Arr0[] = {"ABCDEABDECBAECDEDACB"}; vector <string> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[0]))); int Arg1 = 5; int Arg2 = 0; verify_case(3, Arg2, isRandom(Arg0, Arg1)); }
	void test_case_4() { string Arr0[] = {"ABCABCABCABCABCABCABC",
 "ABCABCABCABCABCABCABC"}; vector <string> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[0]))); int Arg1 = 22; int Arg2 = -1; verify_case(4, Arg2, isRandom(Arg0, Arg1)); }
	void test_case_5() { string Arr0[] = {"AAAAAAAAAAAAAAAA",
 "AAAAAAAAAAAAAAAA",
 "AAAAAAAAAAAAAAAA",
 "AAAAAAAAAAAAAAAA",
 "AAAAAAAAAAAAAAAA",
 "AAAAAAAAAAAAAAAA",
 "AAAAAAAAAAAAAAAA",
 "AAAAAAAAAAAAAAAA",
 "AAAAAAAAAAAAAAAA",
 "AAAAAAAAAAAAAAAA"}; vector <string> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[0]))); int Arg1 = 1; int Arg2 = 0; verify_case(5, Arg2, isRandom(Arg0, Arg1)); }
	void test_case_6() { string Arr0[] = {"ADEF"}; vector <string> Arg0(Arr0, Arr0 + (sizeof(Arr0) / sizeof(Arr0[0]))); int Arg1 = 12; int Arg2 = 0; verify_case(6, Arg2, isRandom(Arg0, Arg1)); }

// END CUT HERE
};
// BEGIN CUT HERE 
int main() {
	CDPlayer().run_test(-1);
}
// END CUT HERE
