HDU 1867

#include<bits/stdc++.h>
using namespace std;
int const M=100010;
int to[M];
void getto(char *str){
    int i=-1,j=0,len=strlen(str);
    to[0]=-1;
    while(j<len-1)
        if(i==-1||str[i]==str[j]){
            i++;
            j++;
            to[j]=i;
        }
        else i=to[i];
}
int kmp(char *str1,char *str2){
    int i=0,j=0;
    int l1=strlen(str1),l2=strlen(str2);
    getto(str2);
	while(i<l1&&j<l2){
		if(j==-1||str1[i]==str2[j]){
			i++;
			j++;
		}
		else j=to[j];
	}
	if(i==l1)
 	   return j;
 	return 0;
}
int main(){
	int i,l1,l2;
	char s1[M],s2[M];
	while(cin>>s1>>s2){
		l1=kmp(s1,s2);
		l2=kmp(s2,s1);
		if(l1==l2&&strcmp(s1,s2)<0||l1!=l2&&l1>l2)
			cout<<s1<<s2+l1<<endl;
		else cout<<s2<<s1+l2<<endl;
	}
    return 0;
}