#include <bits/stdc++.h>
using namespace std;
 
string md5(string s){
	string cmd = "echo -n " + s + " | md5sum";
	FILE *fp = popen(cmd.c_str(), "r");
 
	char buf[50];
	fscanf(fp, "%s", buf);
	fclose(fp);
 
	return string(buf);
}
 
int main(){
	string S;
	cin >> S;
 
	cout << md5(md5(S)) << endl;
	return 0;
}