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Name	Size	Permission	Date
a.cpp	2.27 KB	-rwxr-x---	2024-08-28 22:35
cerror.txt	0 B	-rwxr-x---	2024-08-28 22:35
error.txt	0 B	-rwxr-x---	2024-08-28 22:35
submit_info.txt	350 B	-rwxr-x---	2024-08-28 22:35

Rename

#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<vvvi> vvvvi;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;
typedef vector<vvvb> vvvvb;
typedef pair<ll,ll> pi;
typedef pair<ll,pi> ppi;
typedef pair<ll,ppi> pppi;
typedef pair<ll,pppi> ppppi;
#define FOR(i,l,r) for(ll i=l;i<r;i++)
#define REP(i,n) FOR(i,0,n)
#define RFOR(i,l,r) for(ll i=r-1;i>=l;i--)
#define RREP(i,n) RFOR(i,0,n)
#define ALL(x) x.begin(),x.end()
#define F first
#define S second
#define BS(A,x) binary_search(ALL(A),x)
#define LB(A,x) (ll)(lower_bound(ALL(A),x)-A.begin())
#define UB(A,x) (ll)(upper_bound(ALL(A),x)-A.begin())
#define COU(A,x) (UB(A,x)-LB(A,x))
#define sz(c) ((ll)(c).size())
/*
#include<boost/multiprecision/cpp_int.hpp>
namespace mp=boost::multiprecision;
using Bint=mp::cpp_int;
*/
template<typename T>using min_priority_queue=priority_queue<T,vector<T>,greater<T>>;
template<typename T1,typename T2>ostream&operator<<(ostream&os,pair<T1,T2>&p){os<<p.F<<" "<<p.S;return os;}
template<typename T1,typename T2>istream&operator>>(istream&is,pair<T1,T2>&p){is>>p.F>>p.S;return is;}
template<typename T>ostream&operator<<(ostream&os,vector<T>&v){REP(i,sz(v))os<<v[i]<<(i+1!=sz(v)?" ":"");return os;}
template<typename T>istream&operator>>(istream&is,vector<T>&v){for(T&in:v)is>>in;return is;}
template<class T>bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T&a,T b){if(b<a){a=b;return 1;}return 0;}
ld dist(ld x1,ld y1,ld x2,ld y2){return sqrtl((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));}
const ll mod=998244353;
const ld EPS=1e-8;
/*
const ll mod=1000000007;
//*/
int main(){
  ll N;cin>>N;
  vector<string>S(N);
  cin>>S;
  ll ans=0;
  vvvb DP(1<<N,vvb(N,vb(N)));
  REP(i,N)DP[1<<i][i][i]=1;
  vvi b(1<<N);vi e(1<<N);
  REP(i,1<<N)REP(j,N)if((i>>j)%2){
    b[i].emplace_back(j);
    e[i]+=sz(S[j]);
  }
  vvb E(N,vb(N));
  REP(i,N)REP(j,N)if(S[i].back()==S[j][0])E[i][j]=1;
  REP(i,1<<N)for(auto s:b[i])for(auto j:b[i])for(auto k:b[i])if(DP[i-(1<<j)][s][k]&&E[k][j])DP[i][s][j]=1;
  REP(i,1<<N)for(auto j:b[i])for(auto k:b[i])if(DP[i][j][k])chmax(ans,e[i]);
  cout<<ans<<endl;
  return 0;
}