#include<bits/stdc++.h>

using namespace std;

string s1,s2;

int len;

stack<char> st;

vector<char> path;

void dfs (int ipush,int ipop) {

    if (ipush==len&&ipop==len) {

        for (int i=;i<path.size();i++)

        printf ("%c ",path[i]);

        printf ("\n");

        return;

    }

    if (ipush+<=len) {

        st.push(s1[ipush]);

        path.push_back('i');

        dfs(ipush+,ipop);

        st.pop();

        path.pop_back();

    }

    if (ipop+<=len&&!st.empty()&&st.top()==s2[ipop]) {

        char now=st.top();

        st.pop();

        path.push_back('o');

        dfs(ipush,ipop+);

        st.push(now);

        path.pop_back();

    }

}

int main () {

    while (cin>>s1>>s2) {

        len=s1.length();

        printf ("[\n");

        dfs(,);

        printf ("]\n");

    }

    return ;

}