#include<stdio.h>

char buffer[256];
int input, nest, write_index;

int main()
{
   while( (input = getchar()) != EOF )
   {
      if( input == '[' )
      {
         nest++;
      }
      else if( input == ']' )
      {
         nest--;
      }
      else
      {
         buffer[nest < 0 ? write_index++ : 255] = input;
      }
   }
   puts(buffer);
   return 0;
}