#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <iterator>
#include <functional>
#include <complex>
#include <queue>
#include <stack>
#include <cmath>
#include <cassert>
#include <cstring>
#ifdef __GNUC__
#include <ext/hash_map>
#define unordered_map __gnu_cxx::hash_map
#else
#include <unordered_map>
#endif
using namespace std;
typedef long long LL;
typedef complex<double> CMP;
typedef int vert;
typedef vert edge;
typedef vector<edge> edges;
typedef vector<edges> graph;
bool augment( graph& G, int v, vector<vert>& matchTo, bool visited[] )
{
for(int i=0; i<G[v].size(); ++i) {
vert u = G[v][i];
if( visited[u] ) continue;
visited[u] = true;
if( matchTo[u]<0 || augment(G, matchTo[u], matchTo, visited) )
{ matchTo[v]=u, matchTo[u]=v; return true; }
}
return false;
}
template<int NV>
int biMatch( graph& G, int L )
{
vector<vert> matchTo(G.size(), -1);
int ans = 0;
for(vert v=0; v<L; ++v) {
bool visited[NV] = {};
if( augment(G, v, matchTo, visited) )
++ans;
}
return ans;
}
class SwitchesAndLamps { public:
int theMin(vector <string> switches, vector <string> lamps)
{
const int N = switches[0].size();
const int E = switches.size();
vector< vector<bool> > uneq(N, vector<bool>(N));
vector<LL> id(N, 1);
for(int e=0; e<E; ++e) {
for(int s=0; s<N; ++s) {
id[s] = id[s]*2 + (switches[e][s]=='Y' ? 0 : 1);
for(int l=0; l<N; ++l) {
if( switches[e][s] != lamps[e][l] )
uneq[s][l] = true;
}
}
}
graph G(N*2);
for(int s=0; s<N; ++s)
for(int l=0; l<N; ++l)
if( !uneq[s][l] )
G[s].push_back(N+l);
if( N > biMatch<100>(G, N) )
return -1;
map<LL, int> sizes;
int maxSize = 1;
for(int s=0; s<N; ++s)
maxSize = max(maxSize, ++sizes[id[s]]);
return calcNeed(maxSize);
}
int calcNeed(int maxSize)
{
if( maxSize<=1 )
return 0;
return 1 + calcNeed((maxSize+1)/2);
}
};
// BEGIN CUT HERE
#include <ctime>
double start_time; string timer()
{ ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v)
{ os << "{ ";
for(typename vector<T>::const_iterator it=v.begin(); it!=v.end(); ++it)
os << '\"' << *it << '\"' << (it+1==v.end() ? "" : ", "); os << " }"; return os; }
void verify_case(const int& Expected, const int& Received) {
bool ok = (Expected == Received);
if(ok) cerr << "PASSED" << timer() << endl; else { cerr << "FAILED" << timer() << endl;
cerr << "\to: \"" << Expected << '\"' << endl << "\tx: \"" << Received << '\"' << endl; } }
#define CASE(N) {cerr << "Test Case #" << N << "..." << flush; start_time=clock();
#define END verify_case(_, SwitchesAndLamps().theMin(switches, lamps));}
int main(){
CASE(0)
string switches_[] = {"NYNN", "NNYN"};
vector <string> switches(switches_, switches_+sizeof(switches_)/sizeof(*switches_));
string lamps_[] = {"NNNY", "NNYN"};
vector <string> lamps(lamps_, lamps_+sizeof(lamps_)/sizeof(*lamps_));
int _ = 1;
END
CASE(1)
string switches_[] = {"YYN", "YNY", "YYN"};
vector <string> switches(switches_, switches_+sizeof(switches_)/sizeof(*switches_));
string lamps_[] = {"YNY", "NYY", "YNY"};
vector <string> lamps(lamps_, lamps_+sizeof(lamps_)/sizeof(*lamps_));
int _ = 0;
END
CASE(2)
string switches_[] = {"NYYYNYNNYYYNYNNNNY",
"NYYYNYNNYYYNYNNNNY"};
vector <string> switches(switches_, switches_+sizeof(switches_)/sizeof(*switches_));
string lamps_[] = {"YYYNNNYNNYNYNYNYNY",
"YYYNNNYNNYNYYNNYNY"};
vector <string> lamps(lamps_, lamps_+sizeof(lamps_)/sizeof(*lamps_));
int _ = -1;
END
CASE(3)
string switches_[] = {"YYNNN", "NNYYN"};
vector <string> switches(switches_, switches_+sizeof(switches_)/sizeof(*switches_));
string lamps_[] = {"NYNNY", "NNNYY"};
vector <string> lamps(lamps_, lamps_+sizeof(lamps_)/sizeof(*lamps_));
int _ = -1;
END
CASE(4)
string switches_[] = {"YNNYNNYNYY", "NYNNYNYNYN", "YNYNYYYYYN", "NNYYNYNYNN"};
vector <string> switches(switches_, switches_+sizeof(switches_)/sizeof(*switches_));
string lamps_[] = {"NYYNYNNYNY", "NYYYNNYNNN", "YYYYNYNNYY", "YNNNNYNYYN"};
vector <string> lamps(lamps_, lamps_+sizeof(lamps_)/sizeof(*lamps_));
int _ = 2;
END
CASE(5)
string switches_[] = {"YYNNN", "YNNNN", "NYNNN"};
vector <string> switches(switches_, switches_+sizeof(switches_)/sizeof(*switches_));
string lamps_[] = {"YYNNN", "YNNNN", "NNYNN"};
vector <string> lamps(lamps_, lamps_+sizeof(lamps_)/sizeof(*lamps_));
int _ = -1;
END
CASE(6)
string switches_[] = {"YYNNN", "YNNNN", "NYNNN"};
vector <string> switches(switches_, switches_+sizeof(switches_)/sizeof(*switches_));
string lamps_[] = {"YYNNN", "YNNNN", "YNNNN"};
vector <string> lamps(lamps_, lamps_+sizeof(lamps_)/sizeof(*lamps_));
int _ = -1;
END
/*
CASE(6)
string switches_[] = ;
vector <string> switches(switches_, switches_+sizeof(switches_)/sizeof(*switches_));
string lamps_[] = ;
vector <string> lamps(lamps_, lamps_+sizeof(lamps_)/sizeof(*lamps_));
int _ = ;
END
*/
}
// END CUT HERE