#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>
using namespace std;
typedef long long LL;
typedef long double LD;
typedef complex<double> CMP;
class Egalitarianism { public:
int maxDifference(vector <string> isFriend, int d)
{
int N = isFriend.size();
int INF = 0x3fffffff;
vector< vector<int> > g(N, vector<int>(N, INF));
for(int x=0; x<N; ++x)
for(int y=0; y<N; ++y)
if(x==y)
g[x][y] = 0;
else if(isFriend[x][y]=='Y')
g[x][y] = 1;
for(int k=0; k<N; ++k)
for(int i=0; i<N; ++i)
for(int j=0; j<N; ++j)
g[i][j] = min(g[i][j], g[i][k]+g[k][j]);
int maxd = 0;
for(int x=0; x<N; ++x)
for(int y=0; y<N; ++y)
maxd = max(maxd, g[x][y]);
return maxd==INF ? -1 : maxd*d;
}
};
// 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(_, Egalitarianism().maxDifference(isFriend, d));}
int main(){
CASE(0)
string isFriend_[] = {"NYN",
"YNY",
"NYN"};
vector <string> isFriend(isFriend_, isFriend_+sizeof(isFriend_)/sizeof(*isFriend_));
int d = 10;
int _ = 20;
END
CASE(1)
string isFriend_[] = {"NN",
"NN"};
vector <string> isFriend(isFriend_, isFriend_+sizeof(isFriend_)/sizeof(*isFriend_));
int d = 1;
int _ = -1;
END
CASE(2)
string isFriend_[] = {"NNYNNN",
"NNYNNN",
"YYNYNN",
"NNYNYY",
"NNNYNN",
"NNNYNN"};
vector <string> isFriend(isFriend_, isFriend_+sizeof(isFriend_)/sizeof(*isFriend_));
int d = 1000;
int _ = 3000;
END
CASE(3)
string isFriend_[] = {"NNYN",
"NNNY",
"YNNN",
"NYNN"};
vector <string> isFriend(isFriend_, isFriend_+sizeof(isFriend_)/sizeof(*isFriend_));
int d = 584;
int _ = -1;
END
CASE(4)
string isFriend_[] = {"NYNYYYN",
"YNNYYYN",
"NNNNYNN",
"YYNNYYN",
"YYYYNNN",
"YYNYNNY",
"NNNNNYN"};
vector <string> isFriend(isFriend_, isFriend_+sizeof(isFriend_)/sizeof(*isFriend_));
int d = 5;
int _ = 20;
END
CASE(5)
string isFriend_[] = {"NYYNNNNYYYYNNNN",
"YNNNYNNNNNNYYNN",
"YNNYNYNNNNYNNNN",
"NNYNNYNNNNNNNNN",
"NYNNNNYNNYNNNNN",
"NNYYNNYNNYNNNYN",
"NNNNYYNNYNNNNNN",
"YNNNNNNNNNYNNNN",
"YNNNNNYNNNNNYNN",
"YNNNYYNNNNNNNNY",
"YNYNNNNYNNNNNNN",
"NYNNNNNNNNNNNNY",
"NYNNNNNNYNNNNYN",
"NNNNNYNNNNNNYNN",
"NNNNNNNNNYNYNNN"}
;
vector <string> isFriend(isFriend_, isFriend_+sizeof(isFriend_)/sizeof(*isFriend_));
int d = 747;
int _ = 2988;
END
/*
CASE(6)
string isFriend_[] = {"NY",
"YN"};
vector <string> isFriend(isFriend_, isFriend_+sizeof(isFriend_)/sizeof(*isFriend_));
int d = 0;
int _ = 0;
END
CASE(7)
string isFriend_[] = ;
vector <string> isFriend(isFriend_, isFriend_+sizeof(isFriend_)/sizeof(*isFriend_));
int d = ;
int _ = ;
END
CASE(8)
string isFriend_[] = ;
vector <string> isFriend(isFriend_, isFriend_+sizeof(isFriend_)/sizeof(*isFriend_));
int d = ;
int _ = ;
END
*/
}
// END CUT HERE