#include <stdio.h>
#include <stdlib.h>

void encode(char c1, char c2) {
    printf("%d ", c1 * 16 + c2);
}

void decode(int code) {
    if (code >= 0 && code <= 255) {
        printf("%c ", code / 16);
        printf("%c ", code % 16);
    } else {
        printf("n/a ");
    }
}

int main(int argc, char *argv[]) {
    if (argc != 2) {
        printf("Usage: %s <mode>\n", argv[0]);
        return 1;
    }

    int mode = atoi(argv[1]);

    if (mode == 0) {
        char c1, c2;
        while (scanf("%c %c ", &c1, &c2) == 2) {
            encode(c1, c2);
        }
    } else if (mode == 1) {
        int code;
        while (scanf("%d ", &code) == 1) {
            decode(code);
        }
    } else {
        printf("Invalid mode. Use 0 for encoding or 1 for decoding.\n");
        return 1;
    }

    return 0;
}