#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <stdlib.h>

#define MAX_SIZE 100

struct Stack {
    char data[MAX_SIZE];
    int size;
} stack;

int main() {
    char code[MAX_SIZE];
    stack.size = 0;

    if (fgets(code, sizeof(code), stdin) == NULL) {
        printf("Error reading input.\n");
        return 1;
    }

    if (code[strlen(code) - 1] == '\n') {
        code[strlen(code) - 1] = '\0';
    }

    printf("Read: %s\n", code);

    char missing_closing[MAX_SIZE];
    int missing_count = 0;

    if (strlen(code) > MAX_SIZE) {
        return 1;
    }

    for (int i = 0; code[i] != '\0'; i++) {
        if (code[i] == '(' || code[i] == '[' || code[i] == '{' || code[i] == '<') {
            if (stack.size < MAX_SIZE) {
                stack.data[stack.size++] = code[i];
            } else {
                exit(0);
            }
        } else if (code[i] == ')' || code[i] == ']' || code[i] == '}' || code[i] == '>') {
            if (stack.size == 0) {
                printf("Unexpected closing bracket %c in %d\n", code[i], i);
                return 0;
            }

            char opening = stack.data[stack.size - 1];
            stack.size--;

            if ((code[i] == ')' && opening != '(') ||
                (code[i] == ']' && opening != '[') ||
                (code[i] == '}' && opening != '{') ||
                (code[i] == '>' && opening != '<')) {
                printf("Crossed bracket %c in %d, expected %c\n", code[i], i, opening);
                return 0;
            }
        }
    }

    while (stack.size > 0) {
        char unclosed = stack.data[--stack.size];
        missing_closing[missing_count++] = (unclosed == '(') ? ')' : (unclosed == '[') ? ']' : (unclosed == '{') ? '}' : '>';

        if (missing_count >= MAX_SIZE) {
            exit(0);
        }
    }

    if (missing_count > 0) {
        printf("Missing closing brackets: %s\n", missing_closing);
    } else {
        printf("All brackets OK\n");
    }

    return 0;
}