#include <bits/stdc++.h>
#define all(x) x.begin(), x.end()
#define sz(x) (int) x.size()
#define endl '\n'
#define pb push_back
#define _ ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ii = pair<int,int>;
using iii = tuple<int,int,int>;
const int inf = 2e9+1;
const int mod = 1e9+7;
const int maxn = 1e5+100;
template<typename X, typename Y> bool ckmin(X& x, const Y& y) { return (y < x) ? (x=y,1):0; }
template<typename X, typename Y> bool ckmax(X& x, const Y& y) { return (x < y) ? (x=y,1):0; }
struct trie{
trie *alpha[27], *parent;
bool later, isEnd;
trie(trie *p){
for(int i=0;i<27;++i)alpha[i] = nullptr;
later = 0, parent = p, isEnd = 0;
}
}*Trie;
int mx;
trie *deepest;
void dfs(trie *cur, int height){
if(ckmax(mx,height))deepest = cur;
for(int i=0;i<26;++i){
if(cur->alpha[i]!=nullptr){
dfs(cur->alpha[i],height+1);
}
}
}
vector<char>ans;
void dfs2(trie *cur){
int last = -1;
if(cur->isEnd==1)ans.pb('P');
for(int i=0;i<26;++i){
if(cur->alpha[i]!=nullptr){
if(cur->alpha[i]->later==1)last = i;
else{
ans.pb(char('a'+i));
dfs2(cur->alpha[i]);
}
}
}
if(last!=-1){
ans.pb(char('a'+last));
dfs2(cur->alpha[last]);
}
if(cur->later==0)ans.pb('-');
}
int main(){_
int n;cin>>n;
Trie = new trie(nullptr);
for(int i=1;i<=n;++i){
string s;cin>>s;
trie *cur = Trie;
for(auto x:s){
int ch = x - 'a';
if(cur->alpha[ch]==nullptr)cur->alpha[ch] = new trie(cur);
cur = cur->alpha[ch];
}
cur->isEnd = 1;
}
dfs(Trie, 1);
while(deepest!=nullptr){
deepest->later = 1, deepest = deepest->parent;
}
dfs2(Trie);
cout<<sz(ans)<<endl;
for(auto x:ans)cout<<x<<endl;
}
