/*

clj:水题别人都满分你不是你就完了，所以说水题一定要细心一点，有这么几个细节：①前导零的处理，全是零的时候要特判②换行要注意，不要多大一行，剩下就是水水的模拟了

*/

#include<iostream>

#include<cstdio>

#include<string>

#include<cstring>

#include<algorithm>

#include<cmath>

#include<vector>

#define ll long long

#define fo(i,l,r) for(int i = l;i <= r;i++)

#define fd(i,l,r) for(int i = r;i >= l;i--)

using namespace std;

const int maxn = ;

ll read(){

    ll x=,f=;

    char ch=getchar();

    while(!(ch>=''&&ch<='')){if(ch=='-')f=-;ch=getchar();};

    while(ch>=''&&ch<=''){x=x*+(ch-'');ch=getchar();};

    return x*f;

}

bool visa[maxn],visb[maxn],oka,okb;

char a[maxn],b[maxn];

int n;

int main(){

    freopen("number.in","r",stdin);

    freopen("number.out","w",stdout);

    do{

        a[++n] = getchar();

    }while(a[n]>=''&&a[n]<='');

    n--;

    fo(i,,n){

        b[i] = getchar();

    }

    fo(i,,n){

        if(a[i] >= b[i]) visa[i] = true,oka = true;

        if(a[i] <= b[i]) visb[i] = true,okb = true;

    }

    bool buga = false,bugb = false;

    if(!oka) cout<<"BOOM"<<endl;

    else{

        fo(i,,n) if(visa[i]){

            if(a[i] != '' || i == n) buga = true;

            if(a[i] == '' && !buga) continue;

            cout<<a[i];

        }

        cout<<endl;

    }

    if(!okb) cout<<"BOOM"<<endl;

    else{

        fo(i,,n) if(visb[i]){

            if(b[i] != '' || i == n) bugb = true;

            if(b[i] == '' && !bugb) continue;

            cout<<b[i];

        }

    }

    return ;

}