#include<iostream>
#include<cstdio>
using namespace std;
int a[505];
string s[505];
char c;
int d1,d2;
int top;
int main(){
	freopen("extract.in","r",stdin);
	freopen("extract.out","w",stdout);
	while(cin>>c){
		if(c>='0'&&c<='9'){
			a[top]=a[top]*10+(c-'0');
		}
		if(c>='A'&&c<='Z'){
			s[top]+=c;
		}
		if(c=='['){
			a[top+1]=0;
			s[top+1]="";
			top++;
		}
		if(c==']'){
			for(int i=1;i<=a[top];i++){
				s[top-1]+=s[top];
			} 
			top--;
		}
	}
	cout<<s[0];
	fclose(stdin);
	fclose(stdout);
	return 0;
}