#include <bits/stdc++.h>
#define newline '\n'
#define uns unsigned
#define ll long long
#define deb(x) clog << x << ' '
#define debnewL(x) clog << x << newline
using namespace std;
///*********************

string s;
uns it, nrp;

inline void PassSpecChars()
{
    while(it < s.size() && strchr("[]", s[it]))
    {
        if (s[it] == '[')
            nrp++;
        else
            nrp--;
        it++;
    }
}

inline string eval()
{
    PassSpecChars();
    if (it == s.size() - 1)
        return "";

    int nr = 0;
    while (it < s.size() && isdigit(s[it]))
    {
        nr = nr * 10 + int(s[it] - '0');
        it++;
    }

    PassSpecChars();
    string r = "";
    while (it < s.size() && (isalpha(s[it]) or isdigit(s[it])) && s[it] != ']')///2[a2[b]]
    {
        if (isdigit(s[it]))
        {
            r += eval();
            it++;
            continue;
        }
        r += s[it];
        it++;
    }

    string cr = r;
    while (--nr)
        r += cr;

    if (it < s.size() - 1 && !nrp)
    {
        if (isdigit(s[it]))
            r += eval();
    }
    return r;
}

int main()
{
    getline(cin, s);
    do
    {
        cout << eval();
        it++;
    }
    while (it < s.size());

    return 0;
}