char *getline2(FILE *f) {
    int sym;
    unsigned char *mystring = malloc(1 * sizeof(unsigned char));
    int capacity = 1;
    if (f == NULL) {
        return NULL;
    }
    while (1) {
        sym = fgetc(f);
        if (sym == (int) '\n') {
            capacity+=2;
            mystring = (unsigned char*) realloc (mystring,capacity);
            if(!mystring) {
                return NULL;
            }
            int len = strlen(mystring);
            mystring[len-1] = '\n';
            mystring[len] = '\0';
            return mystring;
        }
        if (sym == EOF) {
            if (feof(f) != 0) {
                if(strlen(mystring) == 0){
                    return NULL;
                }
                ++capacity;
                mystring = (unsigned char*) realloc (mystring,capacity);
                if(!mystring) {
                    return NULL;
                }
                int len = strlen(mystring);
                mystring[len] = '\0';
                return mystring;
            } else {
                return NULL;
            }
        }

        int len = strlen(mystring);
        mystring[len] = sym;

        ++capacity;
        mystring = (unsigned char*) realloc (mystring,capacity);
        if(!mystring) {
            return NULL;
        }
    }
}