#include <stdio.h>
#include <string.h>
#include <ctype.h>
#define UNCLOSED -960
#define MAXLINE 100

enum status {OUT,IN_STRING,IN_COMMENT,S_BRACKET,R_BRACKET,CL_BRACKET,CR_BRACKET,NEW_LINE,END};
char peek(void);
char pop(void);
void add(char);
int c_bracket = 0;       /* curly brackets */
int r_bracket = 0;
int s_bracket = 0;
void printerr(char [],int,int);
void fresh(void);
int readline(char [],int);

int main() {
    int c;
    int state = OUT;
    int linenum = 0;
    char line[MAXLINE+1];
    int ind = 0;
    if(readline(line,MAXLINE))
        while((c = line[ind++]) != EOF)
            switch(state){
                case OUT:
                    if(c =='(' || c=='[')
                        add(c);
                    else if(c==')' || c==']')
                        c==peek()?pop():printerr(line,linenum,c);
                    else if(c=='{')
                        state = CL_BRACKET,c_bracket++;
                    else if(c=='}')
                        state = CR_BRACKET,c_bracket--;
                    else if(c=='/')
                        state = IN_COMMENT;
                    else if(c=='\"')
                        state = IN_STRING;
                    else if(c=='\n')
                        state = NEW_LINE;
                    break;
                case IN_COMMENT:
                    if(c=='*')
                        state = OUT;
                    break;
                case IN_STRING:
                    if(c=='\"')
                        state = OUT;
                    break;
                case NEW_LINE:
                    if(r_bracket!=0||s_bracket!=0)
                        printerr(line,linenum,UNCLOSED);
                    fresh();
                    readline(line,MAXLINE);
                    ind = 0;
                    state = OUT;
                    break;
            }


    return 0;
}


char stack[MAXLINE];
int ind=-1;

int readline(char line[],int maxline){
    int ind = 0;
    while((line[ind] = getchar())!= EOF&&line[ind]!='\n')
        ind++;
    if(ind>0)
        line[++ind] = '\0';
    return ind;
}

void printerr(char line[],int linenum,int bracket){
    if(bracket==UNCLOSED)
        printf("an error occured at line %d:\n%sbracket left unclosed\n",linenum,line);
    else
        printf("an error occured at line %d:\n%splease examine %c\n",linenum,line,(char)bracket);
}

char peek(void){
    if(ind<0)
        return 0;
    return stack[ind];
}

char pop(void){
    if(ind<0)
        return 0;
    stack[ind]==')'?r_bracket--:s_bracket--;
    return stack[ind--];
}

void add(char a){
    if(a=='(')
        stack[++ind] = ')',r_bracket++;
    if(a==']')
        stack[++ind] = ']',s_bracket++;
}

void fresh(){
    ind = -1;
    r_bracket = 0;
    s_bracket = 0;
}