#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("bac.txt");

int main()
{
    int n,P[10]={0},U[10]={0},lmax=0,i=0;
    while(fin>>n)
    {
        i++;
        if(P[n]==0) P[n]=U[n]=i;
        else U[n]=i;
    }
    for(int c=0;c<=9;c++)
        if(U[c]-P[c]+1>lmax) lmax=U[c]-P[c]+1;
    cout<<lmax<<endl;
    for(int c=0;c<=9;c++)
        if(U[c]-P[c]+1==lmax) cout<<c<<" ";
    return 0;
}