#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>


int main(){
    int i;
    int x1, x2;
    int ecrit, lu;
    int p[2];

    pipe(p);
    for (i=0; i<3; i++){
        x1 = fork();
        if (i==0 && x1==0){
            x2 = fork();
            if (x2 == 0){
                read(p[0],&lu,sizeof(int));
                printf("%d received %d\n", getpid(), lu);
                close(p[0]);
            }
        }
        if (i==1 && x1==0){
            x2 = fork();
            if (x2==0){
                ecrit = getpid();
                write(p[1],&ecrit,sizeof(int));
                close(p[1]);
            }
        }
    }
    return EXIT_SUCCESS;
}