This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
vector<char> ans;
struct arbol{
    char letra;
    int palabra_mayor;
    bool fin_palabra=false;
    int hijos[28];
};
int aux,desocupado=1;
arbol raices[500002];
int dfs(int posicion){
    int tam=0;
    for(int i=0;i<28;i++){
        if(raices[posicion].hijos[i]!=0){
            tam=max(dfs(raices[posicion].hijos[i]),tam);
        }
    }
    tam++;
    raices[posicion].palabra_mayor=tam;
    return tam;
}
void res(int pos, bool rama){
    if(pos!=0) {
            ans.push_back(raices[pos].letra);
    }
    if(raices[pos].fin_palabra==true) {
            ans.push_back('P');
    }
    int m=-1;
    for(int i=0;i<28;i++){
        if(raices[pos].hijos[i]!=0){
            if(raices[raices[pos].hijos[i]].palabra_mayor==raices[pos].palabra_mayor-1&&m==-1) m=i;
            else res(raices[pos].hijos[i],false);
        }
    }
    if(pos==0&&m!=-1) res(raices[pos].hijos[m],true);
    else if(m!=-1) res(raices[pos].hijos[m],rama);
    if(pos!=0&&rama==false) {
            ans.push_back('-');
    }
}
int main()
{
    ios_base::sync_with_stdio();cin.tie(0);
    int n;
    cin>>n;
    string palabra;
    for(int i=0;i<n;i++){
        cin>>palabra;
        aux=0;
        for(char l:palabra){
            if(raices[aux].hijos[l-'a']!=0) aux=raices[aux].hijos[l-'a'];
            else{
                raices[aux].hijos[l-'a']=desocupado;
                aux=desocupado;
                raices[aux].letra=l;
                desocupado++;
            }
        }
        raices[aux].fin_palabra=true;
    }
    dfs(0);
    res(0,false);
    cout<<ans.size()<<endl;
    for(char r:ans){
        cout<<r<<endl;
    }
    return 0;
}
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