#include <iostream>
    #include <cstdio>
    #include <cmath>
    #include <set>
    #include <vector>
    #include <string>
    #include <stack>

    using namespace std;
    #define pb push_back
    #define mp pake_pair

    struct tag
    {
            string ss;
            bool open;//1 - da, 0 - net
            tag(){}
            tag(string _ss, bool _open)
            {
                    ss = _ss;
                    open = _open;
            }
    };
    bool chek(string st)
    {
            vector<tag>v;
            stack<tag>tags;
            if (st[0] != '<') {return 0;}
            if (st[st.size()-1] != '>') {return 0;}
            for (int i = 0; i < st.size()-1; i++)
            {
                    if (st[i] == '<')
                    {
                            int k = i+1;
                            bool zakr = 0;
                            if (st[k] == '/')
                            {
                                    zakr = 1;
                                    k++;
                            }
                            else
                                    if (st[k] <= 'a' && st[k] >= 'z')
                                            {return 0;}
                            int kollet = 0;
                            string tmp = "";
                            while (st[k] >= 'a' && st[k] <= 'z' && k < st.size())
                            {
                                    kollet++;
                                    tmp += st[k];
                                    k++;
                            }
                            if (kollet == 0)
                                    { return 0;}
                            if (st[k] != '>') {return 0;}
                            if (k+1 < st.size() && st[k + 1] != '<') {return 0;}
                            i = k;
                            if (zakr)
                                    v.pb(tag(tmp,0));
                            else
                                    v.pb(tag(tmp,1));
                    }
            }
            for (int i = 0; i < v.size(); i++)
            {
                    if (v[i].open)
                            tags.push(v[i]);
                    else
                    {
                            if (tags.empty()){return 0;}
                            if (v[i].ss == tags.top().ss)
                                    tags.pop();
                            else
                                    {return 0;}
                    }
            }
            if (!tags.empty()){return 0;}
            return 1;
    }

    int main()
    {
            freopen("xml.in", "r", stdin);
            freopen("xml.out", "w", stdout);
            string stri;
            cin >> stri;
            string s = stri;
            int i = 0, j = 0;
            while (i < stri.size())
            {
                    s = stri;
                    for (j = 0; j < 26; j++){
                    s[i] =char(j+'a');
                    if (chek(s) == 1)
                    {
                            cout << s;
                            return 0;
                    }
                    }
                    s[i] = '<';
                    if (chek(s))
                    {
                            cout << s;
                            return 0;
                    }
                    s[i] = '>';
                    if (chek(s))
                    {
                            cout << s;
                            return 0;
                    }
                    s[i] = '/';
                    if (chek(s))
                    {
                            cout << s;
                            return 0;
                    }
                    i++;
            }
            return 0;
    }