#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i,a,b) for (ll i = a; i < b; i++)
int main() {
string alpha = "azertyuiopqsdfghjklmwxcvbn";
REP(i,0,26) {
REP(j,0,26) {
cout << alpha[i] << alpha[j] << " ";
}
}
cout << endl;
//cout << "a z e r t y u i o p q s d f g h j k l m w x c v b n" << endl;
cout << 26*26 << endl;
//cout << "a z e r t y u i o p q s d f g h j k l m w x c v b n" << endl;
REP(i,0,26) {
REP(j,0,26) {
cout << alpha[i] << alpha[j] << endl;
}
}
// REP(i,0,26) {
// cout << 'a'+i << endl;
// }
}