#include<iostream>
#include<queue>
#include<vector>
#include<set>
#include<cmath>
#include <map>
#include<math.h>
#include<cstring>
#include<string>
typedef long double ld;

typedef long long ll;
using namespace std;

vector<string> V;
string a;
map <string, int > pie;
void calc( int x){
	if (x>=a.length())return;
	string cas;
	if (a.length() - x >= 2){
			//cout << cas << '\n';
		cas = a.substr(x, 3);
		reverse(cas.begin(), cas.end());
		if (pie[cas] != 0)
		{
			return;
		}
		if (cas.length()>1&&pie[cas]==0)
			V.push_back(cas);
		++pie[cas];
		calc(x + 3);
		--pie[cas];

	}
	 if (a.length() - x >= 1){
		  cas = a.substr(x, 2);
		  if (pie[cas] != 0)
		  {
			  return;
		  }
		  reverse(cas.begin(), cas.end());
		  if (cas.length()>1 )  V.push_back(cas);
		  ++pie[cas];
		  calc(x + 2);
		  --pie[cas];
	 }
	 else return;
}
int main(){

	cin >> a;
	if (a.length() == 5){
		cout << 0;
		return 0;
	}
	a.erase(0, 5);
	reverse(a.begin(), a.end());
	//cout << a << '\n';
	calc(0);

	sort(V.begin(), V.end());
	map<string,int> rep;


	vector<string > ans;
	for (int i = 0; i < V.size(); i++){
		if (rep[V[i]] == 0)ans.push_back(V[i]);
		++rep[V[i]];

	}
	cout << ans.size()<<'\n';
	for (int i = 0; i < ans.size(); ++i){
		cout << ans[i] << '\n';
	}
}