// editor5
#include <stdio.h>
#include <string.h>
#include <ctype.h>

int main() {
    int n, limit;
    char names;
    int i, count = 0;

    scanf("%d %d", &n, &limit);

    for (i = 0; i < n; i++) {
        scanf("%s", names[count]);
        int j, valid = 1;
        for (j = 0; names[count][j]; j++) {
            if (!isalnum(names[count][j])) valid = 0;
        }
        if (!valid) {
            printf("Invalid input\n");
            return 0;
        }
        count++;
        if (count > limit) {
            // Remove oldest by shifting
            int k;
            for (k = 1; k < count; k++) {
                strcpy(names[k-1], names[k]);
            }
            count--;
        }
    }

    // Print from newest to oldest
    for (i = count-1; i >= 0; i--) {
        printf("%s", names[i]);
        if (i != 0) printf(" ");
    }
    printf("\n");
    return 0;
}