#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#define GOOD_LUCK ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define ll long long
#define itn int
#define endl "\n"
#define ff first
#define ss second
#define pb push_back
#define ppb pop_back
#define ins insert
#define lb lower_bound
#define ub upper_bound
#define bs binary_search
#define count1 __builtin_popcount
#define all(v) v.begin(), v.end()
#define unset unordered_set
#define unmap unordered_map
#define pqueue priority_queue
#define ordered_set_less tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
#define ordered_set_greater tree<int, null_type, greater<int>, rb_tree_tag, tree_order_statistics_node_update>
using namespace std;
using namespace __gnu_pbds;
struct point{
};
int ctoi(char x) {
return (int)x - 'a';
}
int sumab(int a, int b) {
return (a + b) * (b - a + 1) / 2;
}
int gcd(int a, int b) {
return (b == 0 ? a : gcd(b, a % b));
}
int lcm(int a, int b) {
return a / gcd(a, b) * b;
}
void print(vector <auto> &v) {
for (const auto &i : v) cout << i << ' ';
}
void print_p(vector <pair<auto, auto>> &v) {
for (const auto &i : v) cout << i.ff << ' ' << i.ss << endl;
}
int compress(int n, vector <int> &v) {
vector <pair<int, int>> x(n);
for (int i=0; i < n; i++) {
x[i] = {v[i], i};
}
sort(all(x));
int nxt=1;
for (int i=0; i < n-1; i++) {
if (x[i].ff == x[i+1].ff) {
x[i].ff = nxt;
}
else x[i].ff = nxt++;
}
x[x.size()-1].ff = nxt;
for (int i=0; i < n; i++) {
swap(x[i].ff, x[i].ss);
}
sort(all(x));
for (int i=0; i < n; i++) {
v[i] = x[i].ss;
}
return nxt;
}
int compress_p(int n, vector <pair<int, int>> &v) {
vector <pair<int, int>> q;
for (int i=0; i < n; i++) {
q.pb({v[i].ff, i});
q.pb({v[i].ss, i});
}
sort(all(q));
int nxt=0;
for (int i=0; i < 2 * n - 1; i++) {
if (q[i].ff == q[i+1].ff) q[i].ff = nxt;
else q[i].ff = nxt++;
}
q.back().ff = nxt;
for (auto &i : q) swap(i.ff, i.ss);
sort(all(q));
for (int i=0; i < 2*n; i+=2) {
v[i/2].ff = q[i].ss;
v[i/2].ss = q[i+1].ss;
}
return nxt;
}
void timelimit() {
int x = 1e+9;
while (x--) x++;
}
void runtime() {
int x = 1, y = 0;
cout << x / y;
}
constexpr int MAX =450000, INF = 1e+9, MOD = 1e+9 + 7, K = 18;
vector <unordered_map<int, int>> g(MAX+2);
vector <int> cnt(MAX+2, 0);
vector <char> st, is(MAX+2, 0);
set <int> use;
int nxt=1;
int res=0;
bool check(int x) {
int sz = use.size();
use.insert(x);
if (sz == use.size()) return 0;
return 1;
}
void add(string k) {
int u = 1;
// cout << "a";
int sz = k.size();
cnt[u] = max(cnt[u], sz);
for (int i=0; i < k.size(); i++) {
int x = ctoi(k[i]);
if (g[u][x] == 0) {
if (nxt >= 1e+6) timelimit();
g[u][x] = ++nxt;
}
u = g[u][x];
cnt[u] = max(cnt[u], sz - i - 1);
}
is[u] = 1;
}
void dfs(int u=1) {
if (is[u]) {
if (check(u)) st.pb('P');
}
res++;
vector <array <int, 3>> x;
for (auto &i : g[u]) {
x.pb({cnt[g[u][i.ff]], g[u][i.ff], i.ff});
}
sort(all(x));
for (auto &i : x) {
st.pb((char)(i[2] + 'a'));
dfs(i[1]);
}
st.pb('-');
res++;
}
void _() {
int n;
cin >> n;
int ma=0;
while (n--) {
string k;
cin >> k;
add(k);
ma = max(ma, (int)k.size());
}
dfs();
while (st.back() == '-') st.ppb();
cout << st.size() << endl;
for (char &i : st) cout << i << endl;
}
signed main() {
// cout << 'a';
// GOOD_LUCK
// freopen("input.txt", "r", stdin);
// freopen("output.txt", "w", stdout);
freopen("log.txt", "w", stderr);
int tests=1;
// cin >> tests;
for (int i=1; i <= tests; i++) {
// cout << "Case #" << i << ": ";
_();
// cout << endl;
}
// int n;
// while (cin >> n) {
// _(n);
// cout << endl;
// }
return 0;
}
// Problem X
// by Ekber_Ekber
/*
*/
