#include <stdio.h>

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

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

}
void kernel(unsigned int y) {
  kernel_recursion(0,y);
}

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); }