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

int open_brackets(char a) {
    return (a == '(' || a == '[' || a == '{' || a == '<');
}

int close_brackets(char a) {
    return (a == ')' || a == ']' || a == '}' || a == '>');
}

char brackets(char a) {
    switch (a) {
        case ')':
            return '(';
        case ']':
            return '[';
        case '}':
            return '{';
        case '>':
            return '<';
        default:
            return '\0';
    }
}

int main() {
    char code[100];
    printf("Read: ");
    fgets(code, sizeof(code), stdin);

    int stack[100];
    int skobochka = -1;
    int error = -1;
    char letters[100];
    int letter_i = 0;

    for (int i = 0; code[i] != '\0'; i++) {
        if (isalpha(code[i])) {
            printf("%c", code[i]);
            letters[letter_i++] = code[i];
        }
        if (open_brackets(code[i])) {
            printf(" ");
            stack[++skobochka] = i;
        } else if (close_brackets(code[i])) {
            printf("%c", code[i]);
            if (skobochka == -1) {
                error = i;
                break;
            }
            if (code[stack[skobochka]] != brackets(code[i])) {
                error = i;
                break;
            }
            skobochka--;
        }
    }

    if (error == -1 && skobochka == -1) {
        printf("\nAll brackets OK\n");
    } else if (error == -1) {
        printf("\nClosing bracket at position %d is not paired\n", stack[skobochka]);
    } else {
        printf("\nUnexpected closing bracket %c in %d\n", code[error], error);
    }
    return 0;
}