Language: C++

#include <iostream>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <algorithm>
#include <numeric>
#include <cmath>
#include <limits>
#include <string>

#define rep(i, n) for (int i = 0; i < (n); i++)
#define repr(i, n) for (int i = (n); i > 0; i--)
#define all(x) (x).begin(), (x).end()
using namespace std;
using lint = long long;
using P = pair<int, int>;

int F, H, I, J, K, L, M, N, S, T, U, W;
// lint F, H, I, J, K, L, M, N, S, T, U, W;
// string A, B;
// string ans;
vector<string> text = {
	"aaaaaaaaaa",
	"aaaaaaaaab",
	"aaaaaaaabb",
	"aaaaaaaabc",
	"aaaaaaabbb",
	"aaaaaaabbb",
	"aaaaaaabcc",
	"aaaaaaabcd",
	"aaaaaabbbb",
	"aaaaaabbbc",
	"aaaaaabbcc",
	"aaaaaabbcd",
	"aaaaaabccc",
	"aaaaaabccd",
	"aaaaaabcdd",
	"aaaaaabcde",
	"aaaaabbbbb",
	"aaaaabbbbc",
	"aaaaabbbcc",
	"aaaaabbbcd",
	"aaaaabbccc",
	"aaaaabbccc",
	"aaaaabbcdd",
	"aaaaabbcde",
	"aaaaabcccc",
	"aaaaabcccd",
	"aaaaabccdd",
	"aaaaabccde",
	"aaaaabcddd",
	"aaaaabcddd",
	"aaaaabcdee",
	"aaaaabcdef",
	"aaaabbbbbb",
	"aaaabbbbbc",
	"aaaabbbbcc",
	"aaaabbbbcd",
	"aaaabbbccc",
	"aaaabbbccc",
	"aaaabbbcdd",
	"aaaabbbcde",
	"aaaabbcccc",
	"aaaabbcccd",
	"aaaabbccdd",
	"aaaabbccde",
	"aaaabbcddd",
	"aaaabbcdde",
	"aaaabbcdee",
	"aaaabbcdef",
	"aaaabccccc",
	"aaaabccccd",
	"aaaabcccdd",
	"aaaabcccde",
	"aaaabccddd",
	"aaaabccddd",
	"aaaabccdee",
	"aaaabccdef",
	"aaaabcdddd",
	"aaaabcddde",
	"aaaabcddee",
	"aaaabcddef",
	"aaaabcdeee",
	"aaaabcdeee",
	"aaaabcdeff",
	"aaaabcdefg",
	"aaabbbbbbb",
	"aaabbbbbbc",
	"aaabbbbbcc",
	"aaabbbbbcd",
	"aaabbbbccc",
	"aaabbbbccc",
	"aaabbbbcdd",
	"aaabbbbcde",
	"aaabbbcccc",
	"aaabbbcccd",
	"aaabbbccdd",
	"aaabbbccde",
	"aaabbbcddd",
	"aaabbbcdde",
	"aaabbbcdee",
	"aaabbbcdef",
	"aaabbccccc",
	"aaabbccccd",
	"aaabbcccdd",
	"aaabbcccde",
	"aaabbccddd",
	"aaabbccddd",
	"aaabbccdee",
	"aaabbccdef",
	"aaabbcdddd",
	"aaabbcddde",
	"aaabbcddee",
	"aaabbcddef",
	"aaabbcdeee",
	"aaabbcdeee",
	"aaabbcdeff",
	"aaabbcdefg",
	"aaabcccccc",
	"aaabcccccd",
	"aaabccccdd",
	"aaabccccde",
	"aaabcccddd",
	"aaabcccddd",
	"aaabcccdee",
	"aaabcccdef",
	"aaabccdddd",
	"aaabccddde",
	"aaabccddee",
	"aaabccddef",
	"aaabccdeee",
	"aaabccdeee",
	"aaabccdeff",
	"aaabccdefg",
	"aaabcddddd",
	"aaabcdddde",
	"aaabcdddee",
	"aaabcdddef",
	"aaabcddeee",
	"aaabcddeee",
	"aaabcddeff",
	"aaabcddefg",
	"aaabcdeeee",
	"aaabcdeeef",
	"aaabcdeeff",
	"aaabcdeefg",
	"aaabcdefff",
	"aaabcdefff",
	"aaabcdefgg",
	"aaabcdefgh",
	"aabbbbbbbb",
	"aabbbbbbbc",
	"aabbbbbbcc",
	"aabbbbbbcd",
	"aabbbbbccc",
	"aabbbbbccc",
	"aabbbbbcdd",
	"aabbbbbcde",
	"aabbbbcccc",
	"aabbbbcccd",
	"aabbbbccdd",
	"aabbbbccde",
	"aabbbbcddd",
	"aabbbbcdde",
	"aabbbbcdee",
	"aabbbbcdef",
	"aabbbccccc",
	"aabbbccccd",
	"aabbbcccdd",
	"aabbbcccde",
	"aabbbccddd",
	"aabbbccddd",
	"aabbbccdee",
	"aabbbccdef",
	"aabbbcdddd",
	"aabbbcddde",
	"aabbbcddee",
	"aabbbcddef",
	"aabbbcdeee",
	"aabbbcdeee",
	"aabbbcdeff",
	"aabbbcdefg",
	"aabbcccccc",
	"aabbcccccd",
	"aabbccccdd",
	"aabbccccde",
	"aabbcccddd",
	"aabbcccddd",
	"aabbcccdee",
	"aabbcccdef",
	"aabbccdddd",
	"aabbccddde",
	"aabbccddee",
	"aabbccddef",
	"aabbccdeee",
	"aabbccdeee",
	"aabbccdeff",
	"aabbccdefg",
	"aabbcddddd",
	"aabbcdddde",
	"aabbcdddee",
	"aabbcdddef",
	"aabbcddeee",
	"aabbcddeee",
	"aabbcddeff",
	"aabbcddefg",
	"aabbcdeeee",
	"aabbcdeeef",
	"aabbcdeeff",
	"aabbcdeefg",
	"aabbcdefff",
	"aabbcdefff",
	"aabbcdefgg",
	"aabbcdefgh",
	"aabccccccc",
	"aabccccccd",
	"aabcccccdd",
	"aabcccccde",
	"aabccccddd",
	"aabccccddd",
	"aabccccdee",
	"aabccccdef",
	"aabcccdddd",
	"aabcccddde",
	"aabcccddee",
	"aabcccddef",
	"aabcccdeee",
	"aabcccdeee",
	"aabcccdeff",
	"aabcccdefg",
	"aabccddddd",
	"aabccdddde",
	"aabccdddee",
	"aabccdddef",
	"aabccddeee",
	"aabccddeee",
	"aabccddeff",
	"aabccddefg",
	"aabccdeeee",
	"aabccdeeef",
	"aabccdeeff",
	"aabccdeefg",
	"aabccdefff",
	"aabccdefff",
	"aabccdefgg",
	"aabccdefgh",
	"aabcdddddd",
	"aabcddddde",
	"aabcddddee",
	"aabcddddef",
	"aabcdddeee",
	"aabcdddeee",
	"aabcdddeff",
	"aabcdddefg",
	"aabcddeeee",
	"aabcddeeef",
	"aabcddeeff",
	"aabcddeefg",
	"aabcddefff",
	"aabcddefff",
	"aabcddefgg",
	"aabcddefgh",
	"aabcdeeeee",
	"aabcdeeeef",
	"aabcdeeeff",
	"aabcdeeefg",
	"aabcdeefff",
	"aabcdeefff",
	"aabcdeefgg",
	"aabcdeefgh",
	"aabcdeffff",
	"aabcdefffg",
	"aabcdeffgg",
	"aabcdeffgh",
	"aabcdefggg",
	"aabcdefggg",
	"aabcdefghh",
	"aabcdefghi",
	"abbbbbbbbb",
	"abbbbbbbbc",
	"abbbbbbbcc",
	"abbbbbbbcd",
	"abbbbbbccc",
	"abbbbbbccc",
	"abbbbbbcdd",
	"abbbbbbcde",
	"abbbbbcccc",
	"abbbbbcccd",
	"abbbbbccdd",
	"abbbbbccde",
	"abbbbbcddd",
	"abbbbbcdde",
	"abbbbbcdee",
	"abbbbbcdef",
	"abbbbccccc",
	"abbbbccccd",
	"abbbbcccdd",
	"abbbbcccde",
	"abbbbccddd",
	"abbbbccddd",
	"abbbbccdee",
	"abbbbccdef",
	"abbbbcdddd",
	"abbbbcddde",
	"abbbbcddee",
	"abbbbcddef",
	"abbbbcdeee",
	"abbbbcdeee",
	"abbbbcdeff",
	"abbbbcdefg",
	"abbbcccccc",
	"abbbcccccd",
	"abbbccccdd",
	"abbbccccde",
	"abbbcccddd",
	"abbbcccddd",
	"abbbcccdee",
	"abbbcccdef",
	"abbbccdddd",
	"abbbccddde",
	"abbbccddee",
	"abbbccddef",
	"abbbccdeee",
	"abbbccdeee",
	"abbbccdeff",
	"abbbccdefg",
	"abbbcddddd",
	"abbbcdddde",
	"abbbcdddee",
	"abbbcdddef",
	"abbbcddeee",
	"abbbcddeee",
	"abbbcddeff",
	"abbbcddefg",
	"abbbcdeeee",
	"abbbcdeeef",
	"abbbcdeeff",
	"abbbcdeefg",
	"abbbcdefff",
	"abbbcdefff",
	"abbbcdefgg",
	"abbbcdefgh",
	"abbccccccc",
	"abbccccccd",
	"abbcccccdd",
	"abbcccccde",
	"abbccccddd",
	"abbccccddd",
	"abbccccdee",
	"abbccccdef",
	"abbcccdddd",
	"abbcccddde",
	"abbcccddee",
	"abbcccddef",
	"abbcccdeee",
	"abbcccdeee",
	"abbcccdeff",
	"abbcccdefg",
	"abbccddddd",
	"abbccdddde",
	"abbccdddee",
	"abbccdddef",
	"abbccddeee",
	"abbccddeee",
	"abbccddeff",
	"abbccddefg",
	"abbccdeeee",
	"abbccdeeef",
	"abbccdeeff",
	"abbccdeefg",
	"abbccdefff",
	"abbccdefff",
	"abbccdefgg",
	"abbccdefgh",
	"abbcdddddd",
	"abbcddddde",
	"abbcddddee",
	"abbcddddef",
	"abbcdddeee",
	"abbcdddeee",
	"abbcdddeff",
	"abbcdddefg",
	"abbcddeeee",
	"abbcddeeef",
	"abbcddeeff",
	"abbcddeefg",
	"abbcddefff",
	"abbcddefff",
	"abbcddefgg",
	"abbcddefgh",
	"abbcdeeeee",
	"abbcdeeeef",
	"abbcdeeeff",
	"abbcdeeefg",
	"abbcdeefff",
	"abbcdeefff",
	"abbcdeefgg",
	"abbcdeefgh",
	"abbcdeffff",
	"abbcdefffg",
	"abbcdeffgg",
	"abbcdeffgh",
	"abbcdefggg",
	"abbcdefggg",
	"abbcdefghh",
	"abbcdefghi",
	"abcccccccc",
	"abcccccccd",
	"abccccccdd",
	"abccccccde",
	"abcccccddd",
	"abcccccddd",
	"abcccccdee",
	"abcccccdef",
	"abccccdddd",
	"abccccddde",
	"abccccddee",
	"abccccddef",
	"abccccdeee",
	"abccccdeee",
	"abccccdeff",
	"abccccdefg",
	"abcccddddd",
	"abcccdddde",
	"abcccdddee",
	"abcccdddef",
	"abcccddeee",
	"abcccddeee",
	"abcccddeff",
	"abcccddefg",
	"abcccdeeee",
	"abcccdeeef",
	"abcccdeeff",
	"abcccdeefg",
	"abcccdefff",
	"abcccdefff",
	"abcccdefgg",
	"abcccdefgh",
	"abccdddddd",
	"abccddddde",
	"abccddddee",
	"abccddddef",
	"abccdddeee",
	"abccdddeee",
	"abccdddeff",
	"abccdddefg",
	"abccddeeee",
	"abccddeeef",
	"abccddeeff",
	"abccddeefg",
	"abccddefff",
	"abccddefff",
	"abccddefgg",
	"abccddefgh",
	"abccdeeeee",
	"abccdeeeef",
	"abccdeeeff",
	"abccdeeefg",
	"abccdeefff",
	"abccdeefff",
	"abccdeefgg",
	"abccdeefgh",
	"abccdeffff",
	"abccdefffg",
	"abccdeffgg",
	"abccdeffgh",
	"abccdefggg",
	"abccdefggg",
	"abccdefghh",
	"abccdefghi",
	"abcddddddd",
	"abcdddddde",
	"abcdddddee",
	"abcdddddef",
	"abcddddeee",
	"abcddddeee",
	"abcddddeff",
	"abcddddefg",
	"abcdddeeee",
	"abcdddeeef",
	"abcdddeeff",
	"abcdddeefg",
	"abcdddefff",
	"abcdddefff",
	"abcdddefgg",
	"abcdddefgh",
	"abcddeeeee",
	"abcddeeeef",
	"abcddeeeff",
	"abcddeeefg",
	"abcddeefff",
	"abcddeefff",
	"abcddeefgg",
	"abcddeefgh",
	"abcddeffff",
	"abcddefffg",
	"abcddeffgg",
	"abcddeffgh",
	"abcddefggg",
	"abcddefggg",
	"abcddefghh",
	"abcddefghi",
	"abcdeeeeee",
	"abcdeeeeef",
	"abcdeeeeff",
	"abcdeeeefg",
	"abcdeeefff",
	"abcdeeefff",
	"abcdeeefgg",
	"abcdeeefgh",
	"abcdeeffff",
	"abcdeefffg",
	"abcdeeffgg",
	"abcdeeffgh",
	"abcdeefggg",
	"abcdeefggg",
	"abcdeefghh",
	"abcdeefghi",
	"abcdefffff",
	"abcdeffffg",
	"abcdefffgg",
	"abcdefffgh",
	"abcdeffggg",
	"abcdeffggg",
	"abcdeffghh",
	"abcdeffghi",
	"abcdefgggg",
	"abcdefgggh",
	"abcdefgghh",
	"abcdefgghi",
	"abcdefghhh",
	"abcdefghhh",
	"abcdefghii",
	"abcdefghij
};

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	cin >> N;

	rep(i, pow(2, N - 1)) {
		string ans = "";
		repr(j, N) {
			ans += text[i][10 - j];
		}
		cout << ans << endl;
	}
	return 0;
}

Compiler output:
a.cc:535:9: warning: missing terminating " character
  535 |         "abcdefghij
      |         ^
a.cc:535:9: error: missing terminating " character
  535 |         "abcdefghij
      |         ^~~~~~~~~~~