#include<iostream>
#include<cstring>
std::string duru()
{
    int n;
    std::string s1="\0",s2;
    char s3;
    while(std::cin>>s3)
    {
        if(s3=='[')
        {
            std::cin>>n;
            s1=duru();
            while(--n>=0)
            {

                s2+=duru();
            }
        }
        else if(s3==']')
        {
            return s1;
        }
        else{
            s1=s1+s3;
        }


    }


}
int main()
{
    
	std::cout<<duru()<<std::endl;
	
}