import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();

		char[] a = new char[n];
		Arrays.fill(a, 'a');
		for (int i = 0; i < n; i++) {
			int[] cnt = new int[25];
			for (int j = 0; j < 25; j++) {
				char c = (char) ('a' + j);
				a[i] = c;
				System.out.println("? " + String.valueOf(a));
				cnt[j] = sc.nextInt();
			}
			int j2 = 25;
			for (int j = 1; j < 25; j++) {
				if (cnt[j] != cnt[0]) {
					j2 = j;
					break;
				}
			}
			a[i] = (char) ('a' + j2);
		}
		System.out.println("! " + String.valueOf(a));
		sc.close();
	}
}