#include<stdio.h>
#include<iostream>
#include<string>
#include<stack>
#include<string.h>
using namespace std;
int last,cur,next[100005];
char s[100005];
int main()
{
    while(scanf("%s",s+1)!=EOF)
    {
        int len=strlen(s+1);
        last=cur=0;
        next[0]=0;
        for(int i=1;i<=len;i++)
        {
            if(s[i]=='[') cur=0;
            else
            if(s[i]==']') cur=last;
            else
            {
                next[i]=next[cur];
                next[cur]=i;
                if(cur == last) last = i;
                cur = i;
            }
        }
        for(int i=next[0];i!=0;i=next[i])
            printf("%c",s[i]);
        printf("\n");
    }
    return 0;
}