#include <bits/stdc++.h>

using namespace std;
/// IT IS PRECALC
/// SORRY
/// NOW I WILL FUCK YOUR EYES
/// GOOD LUCK
/// THERE ARE 200(300) STRINGS OF CODE
/// KOLYA TRETYAKOV's CODE
/// COPYRIGHTED
int main()
{
    vector <vector <string> > data(9);
    data[1] = {"a1"};
    data[2] = {"IMPOSSIBLE"};
    data[3] = {"IMPOSSIBLE"};
    data[4] = {"IMPOSSIBLE"};
    data[8] = {
        "a1",
        "b3",
        "a5",
        "b7",
        "c5",
        "a4",
        "b2",
        "c4",
        "a3",
        "b1",
        "c3",
        "a2",
        "b4",
        "a6",
        "b8",
        "c6",
        "a7",
        "b5",
        "c7",
        "a8",
        "b6",
        "c8",
        "d6",
        "e4",
        "d2",
        "f1",
        "e3",
        "c2",
        "d4",
        "e2",
        "c1",
        "d3",
        "e1",
        "g2",
        "f4",
        "d5",
        "e7",
        "g8",
        "h6",
        "f5",
        "h4",
        "g6",
        "h8",
        "f7",
        "d8",
        "e6",
        "f8",
        "d7",
        "e5",
        "g4",
        "h2",
        "f3",
        "g1",
        "h3",
        "g5",
        "h7",
        "f6",
        "e8",
        "g7",
        "h5",
        "g3",
        "h1",
        "f2",
        "d1"
    };
    data[7] = {"a1",
        "b3",
        "a5",
        "b7",
        "c5",
        "a4",
        "b2",
        "c4",
        "a3",
        "b1",
        "c3",
        "a2",
        "b4",
        "a6",
        "c7",
        "b5",
        "a7",
        "c6",
        "d4",
        "c2",
        "e1",
        "d3",
        "c1",
        "e2",
        "f4",
        "g2",
        "e3",
        "d1",
        "f2",
        "g4",
        "e5",
        "g6",
        "e7",
        "d5",
        "b6",
        "d7",
        "f6",
        "e4",
        "d6",
        "f7",
        "g5",
        "e6",
        "g7",
        "f5",
        "g3",
        "f1",
        "d2",
        "f3",
        "g1"
    };
    data[5] = {
    "a1",
    "b3",
    "a5",
    "c4",
    "a3",
    "b1",
    "d2",
    "e4",
    "c5",
    "a4",
    "b2",
    "d1",
    "c3",
    "b5",
    "d4",
    "e2",
    "c1",
    "a2",
    "b4",
    "d5",
    "e3",
    "c2",
    "e1",
    "d3",
    "e5"
    };
    data[6] = {
    "a1",
    "b3",
    "a5",
    "c4",
    "a3",
    "b1",
    "c3",
    "a2",
    "b4",
    "a6",
    "c5",
    "e6",
    "f4",
    "e2",
    "c1",
    "d3",
    "f2",
    "d1",
    "b2",
    "a4",
    "b6",
    "d5",
    "f6",
    "e4",
    "d2",
    "f1",
    "e3",
    "c2",
    "e1",
    "f3",
    "e5",
    "c6",
    "d4",
    "b5",
    "d6",
    "f5"
    };
    int n;
    cin >> n;
    for (int i = 0; i < data[n].size(); i++) {
        cout << data[n][i] << endl;
    }
}
///AND NOW
///IMPORTANT PART OF THIS PROBLEM
///PROGRAM
///THAT
///DID
///THIS
///SHIT

/*#include <bits/stdc++.h>

using namespace std;

const int INF = 1e9 + 7;

vector <pair <int, int> > mas;

vector <pair <int, int> > mat = {{-2, -1}, {-2, 1}, {-1, -2}, {-1, 2}, {1, -2}, {1, 2}, {2, -1}, {2, 1}};
int n;
bool fl = 0;


void dfs(int x, int y, vector <vector <int> > &used, int cnt) {
    mas.push_back({x, y});
    //cout << cnt << endl;
    if (cnt == n * n) {
        fl = 1;
        return;
    }
    for (int i = 0; i < mat.size(); i++) {
        int x1 = x + mat[i].first;
        int y1 = y + mat[i].second;
        if (x1 < 0 || x1 >= n) continue;
        if (y1 < 0 || y1 >= n) continue;
        if (used[x1][y1]) continue;
        used[x1][y1] = 1;
        dfs(x1, y1, used, cnt + 1);
        if (fl) return;
        used[x1][y1] = 0;
    }
    mas.pop_back();
}

int main() {
    freopen("tests.txt", "w", stdout);
    cin >> n;
    vector <vector <int> > used(n, vector <int> (n, 0));
    used[0][0] = 1;
    dfs(0, 0, used, 1);
    if (!fl) {
        cout << "IMPOSSIBLE";
    } else {
        for (int i = 0; i < mas.size(); i++) {
            char x = (char) (mas[i].first + 'a');
            int y = mas[i].second + 1;
            cout << "~" << x << y << "~";
            if (i != mas.size() - 1) cout << ",";
            cout << endl;
        }
    }
}
*/

///PROGRAM ENDS THERE
///THERE ARE TIME TO SAYING GOODBYE
///SORRY FOR SOME TIME THAT YOU SPENT HERE
///BYE MOTHERFUCKER
///VIZIVAYTE SKORUYU, KOLE PLOHO

///BY THE WAY

///IT'S MY 301 PROBLEM!!!

///SO























///THIS PROGRAM CONTAINS 301 STRINGS
///IT'S JOKE!111!!!!111!!111!!111!11!11!