#include <bits/stdc++.h>

#define all(v) (v).begin(),(v).end()
#define INF int(1e8)
#define NINF int(-1e8)
#define clr(a,v) memset(a,v,sizeof(a))
#define ll long long
#define ull unsigned long long
#define ld long double
#define eps 1e-8
#define PI acos(-1)
#define MOD (ll)(1e9 + 7)
#define readFile freopen("in.txt","r",stdin)
#define fastIO ios::sync_with_stdio(0)

using namespace std;

const int N = 200010;
int sufArr[N], tmpSufArr[N], rank[N], tmpRank[N], lcp[N];
int len;
char text[N];

void radixSort(int k){
    int freq[N] = {0}, mx = max(300,len);
    for(int i = 0; i < len; i++) freq[i+k < len ? rank[i+k] : 0]++;
    int acum = 0;
    for(int i = 0; i < mx; i++){
        int sh = freq[i]; freq[i] = acum;
        acum += sh;
    }
    for(int i = 0; i < len; i++) tmpSufArr[freq[sufArr[i]+k < len ? rank[sufArr[i]+k] : 0 ]++] = sufArr[i];
    for(int i = 0; i < len; i++) sufArr[i] = tmpSufArr[i];
}

void buildSuffixArray(){
    clr(sufArr,0); clr(tmpSufArr,0); clr(rank,0); clr(tmpRank,0);
    for(int i = 0; i < len; i++) sufArr[i] = i, rank[i] = text[i];
    for(int k = 1; k < len; k <<= 1){
        radixSort(k);
        radixSort(0);
        int r = 0;
        tmpRank[sufArr[0]] = r;
        for(int i = 1; i < len; i++)
            if(rank[sufArr[i]]==rank[sufArr[i-1]] && rank[sufArr[i]+k]==rank[sufArr[i-1]+k])
                tmpRank[sufArr[i]] = r;
            else tmpRank[sufArr[i]] = ++r;
        for(int i = 0; i < len; i++) rank[i] = tmpRank[i];
        if(rank[sufArr[len-1]] == len-1) break;
    }
}

void buildLcp(){
    clr(lcp,0);
    int pos[N] = {0}, plcp[N] = {0}, l = 0;
    pos[sufArr[0]] = -1;
    for(int i = 1; i < len; i++) pos[sufArr[i]] = sufArr[i-1];
    for(int i = 0; i < len; i++){
        if(pos[i]==-1){
            plcp[i] = 0;
            continue;
        }
        while(text[i+l] == text[pos[i]+l]) l++;
        plcp[i] = l;
        l = max(l-1,0);
    }
    for(int i = 0; i < len; i++) lcp[i] = plcp[sufArr[i]];
}

int main(){

#ifndef ONLINE_JUDGE
    readFile;
#endif

    char t1[N],t2[N];
    while(scanf("%s",t1) != EOF){

        scanf("%s\n",t2);

        int l1 = strlen(t1), l2 = strlen(t2);

        for(int i = 0; i < l1; i++) text[i] = t1[i];
        text[l1++] = '#';
        for(int i = 0; i < l2; i++) text[i+l1] = t2[i];
        len = strlen(text);
        text[len++] = '$';

        buildSuffixArray();
        buildLcp();

        int lcs = 0;
        for(int i = 1; i < len; i++){
            int ow1 = sufArr[i-1], ow2 = sufArr[i];
            if(ow1>ow2) swap(ow1,ow2);
            if(ow1<l1&&ow2>=l1&&lcp[i]<=(l1-ow1)) lcs = max(lcs,lcp[i]);
        }
        if(!lcs){
            printf("No common sequence.\n\n");
            continue;
        }
        for(int i = 1; i < len; i++){
            if(lcp[i] == lcs){
                int ow1 = sufArr[i-1], ow2 = sufArr[i];
                if(ow1>ow2) swap(ow1,ow2);
                if(ow1<l1&&ow2>=l1&&lcp[i]<=(l1-ow1)){
                    for(int j = sufArr[i]; j < sufArr[i]+lcs; j++) printf("%c",text[j]);
                    printf("\n");
                }
            }
        }
        printf("\n");

    }
    return 0;
}