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

#define MAX_LEN 100

int is_matching_pair(char open, char close) {
    return (open == '(' && close == ')') ||
           (open == '{' && close == '}') ||
           (open == '[' && close == ']') ||
           (open == '<' && close == '>');
}

void check_brackets(const char *code) {
    char stack[MAX_LEN];
    int positions[MAX_LEN];
    int top = -1;
    
    printf("Read: %s\n", code);

    for (int i = 0; i < strlen(code); i++) {
        char ch = code[i];
        
        if (ch == '(' || ch == '{' || ch == '[' || ch == '<') {
            if (top < MAX_LEN - 1) {
                stack[++top] = ch;
                positions[top] = i;
            } else {
                printf("Stack overflow at position %d\n", i);
                return;
            }
        }
        else if (ch == ')' || ch == '}' || ch == ']' || ch == '>') {
            if (top == -1) {
                printf("Unmatched closing bracket %c at position %d\n", ch, i);
                return;
            }
            if (!is_matching_pair(stack[top], ch)) {
                printf("Crossed bracket %c in %d, expected %c\n", ch, i, 
                       stack[top] == '(' ? ')' :
                       stack[top] == '{' ? '}' :
                       stack[top] == '[' ? ']' : '>');
                return;
            }
            top--;
        }
    }
    
    if (top != -1) {
        printf("Unmatched opening bracket %c at position %d, expected %c\n", 
               stack[top], positions[top],
               stack[top] == '(' ? ')' :
               stack[top] == '{' ? '}' :
               stack[top] == '[' ? ']' : '>');
    } else {
        printf("All brackets OK\n");
    }
}

int main() {
    char code[MAX_LEN];
    
    if (fgets(code, MAX_LEN, stdin) != NULL) {
        code[strcspn(code, "\n")] = '\0';
        check_brackets(code);
    }
    
    return 0;
}