#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>
#define N 100005
#define fo(i,l,r) for(int i=l;i<=r;i++)
#define rf(i,r,l) for(int i=r;i>=l;i--)
#define ll long long
using namespace std;
int n,i;char c[N];
string s;
string gs()
{
    string ans="",str="";int sum=0;
    if(s[i++]^'['){ans=s[i-1];return ans;}
    while(s[i]>=48&&s[i]<=57)
        sum=sum*10+(s[i]&15),i++;
    while(s[i]^']')str+=gs();
    while(sum--)ans+=str;i++;
    return ans;
}
void swap(int &x,int &y){int t=x;x=y;y=t;}
int max(int x,int y){return x>y?x:y;}
int min(int x,int y){return x<y?x:y;}
int read(){
	int sum=0;bool f=0;char c=getchar();
	for(;c<48||c>57;c=getchar())if(c==45)f=1;
	for(;c>=48&&c<=57;c=getchar())sum=sum*10+(c&15);
	return f?-sum:sum;
}
int main(){
	freopen("extract.in","r",stdin);freopen("extract.out","w",stdout);
	ios::sync_with_stdio(0);
	cin>>s;n=s.size();
	while(i<n)cout<<gs();
	return 0;
}