#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>
#include <string.h>
int main(int argc, char *argv[]) {
    int p_c1[2], c1_p[2];
    if(pipe(p_c1) < 0 || pipe(c1_p) < 0) {
        perror("Error on first set of pipes");
        exit(1);
    }
    int f1 = fork();
    if(-1 == f1) {
        perror("Error on child 1");
    } else if (0 == f1) {
        close(p_c1[1]);
        close(c1_p[0]);
        int len = 0;
        if(0 >= read(p_c1[0], &len, sizeof(int))) {
            perror("C1 - Error on read length");
            exit(1);
        }
        char *msg = malloc(sizeof(char) * len);
        if(0 >= read(p_c1[0], msg, sizeof(char) * len)) {
            perror("C1 - Error reading message");
            exit(1);
        }
        char *rez = malloc(sizeof(char) * len);
        int count = 0;
        for(int i = 0; i < len; i++) {
            if(msg[i] >= 'a' && msg[i] <= 'e') {
                rez[count++] = msg[i];
            }
        }
        free(msg);
        rez[count++] = 0;

        if(0 > write(c1_p[1], &count, sizeof(int))) {
            perror("C1 - Error writing length");
            exit(1);
        }
        if(count > 0) {
            if(0 > write(c1_p[1], rez, sizeof(char) * count)) {
                perror("C1 - Error writing result");
                exit(1);
            }
        }
        free(rez);
        close(p_c1[0]);
        close(c1_p[1]);
        exit(0);
    }

    close(p_c1[0]);
    close(c1_p[1]);

    int p_c2[2], c2_p[2];
    if(pipe(p_c2) < 0 || pipe(c2_p) < 0) {
        perror("Error on second set of pipes");
        exit(1);
    }
    int f2 = fork();
    if(-1 == f2) {
        perror("Error on child 2");
    } else if (0 == f2) {
        close(p_c2[1]);
        close(c2_p[0]);
        int len = 0;
        if(0 >= read(p_c2[0], &len, sizeof(int))) {
            perror("C2 - Error on read length");
            exit(1);
        }
        char *msg = malloc(sizeof(char) * len);
        if(0 >= read(p_c2[0], msg, sizeof(char) * len)) {
            perror("C2 - Error reading message");
            exit(1);
        }
        char *rez = malloc(sizeof(char) * len);
        int count = 0;
        for(int i = 0; i < len; i++) {
            if(msg[i] >= 'v' && msg[i] <= 'z') {
                rez[count++] = msg[i];
            }
        }
        free(msg);
        rez[count++] = 0;
        if(0 > write(c2_p[1], &count, sizeof(int))) {
            perror("C2 - Error writing length");
            exit(1);
        }
        if(count > 0) {
            if(0 > write(c2_p[1], rez, sizeof(char) * count)) {
                perror("C1 - Error writing result");
                exit(1);
            }
        }
        free(rez);
        close(p_c2[0]);
        close(c2_p[1]);
        exit(0);
    }

    close(p_c2[0]);
    close(c2_p[1]);

    char *in = malloc(sizeof(char) * 100);
    scanf("%s", in);
    int len = strlen(in);
    if(0 > write(p_c1[1], &len, sizeof(int))) {
        perror("P - Error writing message length to C1");
    } else {
        if(0 > write(p_c1[1], in, sizeof(char) * len)) {
            perror("P - Error writing message to C1");
        }
    }

    if(0 > write(p_c2[1], &len, sizeof(int)))  {
        perror("P - Error writing message length to C2");
    } else {
        if(0 > write(p_c2[1], in, sizeof(char) * len)) {
            perror("P - Error writing message to C2");
        }
    }
    free(in);

    int rez_len = 0;
    if (0 >= read(c1_p[0], &rez_len, sizeof(int))) {
        perror("P - Error reading length from C1");
        rez_len = 0;
    }
    if(rez_len > 0) {
        char *rez = malloc(sizeof(char) * rez_len);
        if(0 >= read(c1_p[0], rez, sizeof(char) * rez_len)) {
            perror("P - Error reading message from C1");
        } else {
            printf("First child: %s\n", rez);
        }
        free(rez);
    }

    rez_len = 0;
    if (0 >= read(c2_p[0], &rez_len, sizeof(int))) {
        perror("P - Error reading length from C2");
        rez_len = 0;
    }
    if(rez_len > 0) {
        char *rez = malloc(sizeof(char) * rez_len);
        if(0 >= read(c2_p[0], rez, sizeof(char) * rez_len)) {
            perror("P - Error reading message from C2");
        } else {
            printf("Second child: %s\n", rez);
        }
        free(rez);
    }
    close(p_c1[1]);
    close(c1_p[0]);
    close(p_c2[1]);
    close(c2_p[0]);
    wait(NULL);
    wait(NULL);

    return 0;
}