#include <stdio.h>

void handle_open_port(unsigned int x);
void handle_close_port(unsigned int x);

unsigned int y = 0;
unsigned int z = 0;

void kernel_recursion(unsigned int x) {
    z = y;
    handle_open_port(x);
    if (x < y) kernel_recursion(x + 1);
    handle_close_port(x);

}
void kernel(unsigned int limit) {
    y = z = limit;
    kernel_recursion(0);
    y = z = 0;
}

int main() { kernel(100); }

void handle_open_port(unsigned int x) { printf("OPENING: %u\n", x); }
void handle_close_port(unsigned int x) { printf("CLOSING: %u\n", x); }