#include<bits/stdc++.h>

using namespace std;

string s;
int n = 0;
int whee = 0;

string f(int x , string y){
	string sss;
	for(int i = 0 ; i < x ; i++){
		sss += y;
	}
	return sss;
}

string dfs(){
	string ss;
	while(1){
		if(s[whee] == ']' || whee >= n){
			return ss;
		}
		if(s[whee] == '['){
			int m = s[whee + 1] - '0';
			whee += 2;
			ss += f(m , dfs());
			whee++;
		}
		if(s[whee] != ']')
			ss += s[whee];
		whee++;
	}
}

int main(){
	cin >> s;
	n = s.size();
	cout << dfs();
	return 0;
}