Go: package main

import (
	"bufio"
	"fmt"
	"os"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func main() {
	scanner.Split(bufio.ScanWords)

	str := nextString()
	for i := len(str) - 1; i >= 0; i-- {
		fmt.Print(str[i:(i + 1)])
	}
	fmt.Print("\n")
}

C++: //#define _GRIBCXX_DEBUG
#include <algorithm>
#include <cctype>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iostream>
#include <iomanip>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;


// ?????¬???????????¬??????
#pragma region MACRO
#define P(x) cout << (x) << endl
#define p(x) cout << (x)
#define PED cout << "\n"
#define rep(i,n) for(int i=0; i<(int)n; ++i)
#define REP(i,x,n) for(int i=x; i<(int)n; ++i)
#define repi(i,n) for(int i=0; i<=(int)n; ++i)
#define REPI(i,x,n) for(int i=x; i<=(int)n; ++i)
#define ILP while(true)
#define FOR(i,c) for(__typeof((c).begin())!=(c).begin(); i!=(c).end(); ++i)
#define ALL(c) (c).begin(), (c).end()
#define mp make_pair
#pragma endregion

#pragma region TYPE_DEF
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<string, string> pss;
typedef pair<string, int> psi;
typedef pair<int, string> pis;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<long> vl;
typedef vector<long long> vll;
typedef vector<string> vs;
#pragma endregion


// Effective std
#pragma region ESTD
template<typename C, typename T>
constexpr int count(C& c, T t) { return count(ALL(c), t); }
template<typename C, typename F>
constexpr int count_if(C& c, F f) { return count_if(ALL(c), f); }
template<typename C, typename T, typename U>
constexpr void replace(C& c, T t, U u) { replace(ALL(c), t, u); }
template<typename C, typename F, typename U>
constexpr void replace_if(C& c, F f, U u) { (ALL(c), f, u); }
template<typename C>
constexpr void sort(C& c) { sort(ALL(c)); }
template<typename C, typename Pred>
constexpr void sort(C& c, Pred p) { sort(ALL(c), p); }
template<typename C>
constexpr void reverse(C& c) { reverse(ALL(c)); }
#pragma endregion


// ?´???°
#pragma region PRIME
bool is_prime(unsigned n) {
  switch(n) {
    case 0:
    case 1: return false;
    case 2: return true;
  }
  if (n%2==0) return false;
  for (unsigned i=3; i*i<=n; i+=2)
    if (n%i==0) return false;
  return true;
}
#pragma endregion


// ??§??????/?°?????????????
#pragma region TRANSFORM
void mutal_tr(string &s) {
  for(int i=s.size(); i--;) {
    if(islower(s[i])) s[i] = toupper(s[i]);
    else if (isupper(s[i])) s[i] = tolower(s[i]);
  }
}
void to_upper(string &s) { for(int i=s.size(); i--;) s[i] = toupper(s[i]); }
void to_lower(string &s) { for(int i=s.size(); i--;) s[i] = tolower(s[i]); }
#pragma endregion


// ??????
#pragma region SET
template<class T>
set<T> intersection(const set<T>& sa, const set<T>& sb) {
  set<T> ret;
  for(T a : sa) if(sb.find(a) != sb.end()) ret.insert(a);
  return ret;
}
#pragma endregion

// Union Find
#pragma region UF
struct UnionFind {
  vector<int> data;
  UnionFind(int size) : data(size, -1) {}
  bool union_set(int x, int y) {
    x = root(x); y = root(y);
    if(x!=y) {
      if(data[y] < data[x]) swap(x, y);
      data[x] += data[y]; data[y] = x;
    }
    return x != y;
  }
  bool find_set(int x, int y) { return root(x) == root(y); }
  int root(int x) { return data[x] < 0 ? x : data[x] = root(data[x]); }
  int size(int x) { return -data[root(x)]; }
};
#pragma endregion


// ?????°
#pragma region CONST_VAL
#define PI (2*acos(0.0))
#define EPS (1e-9)
#define MOD (int)(1e9+7)
#pragma endregion

int main()
{
    string s;
    cin >> s;
    reverse(s);
    P(s);

    return 0;
}

C++: #include <stdio.h>
#include <string.h>

int main(){
	int i;
	char str[256];
	char n[256];
	scanf("%s", str);
	int l = strlen(str);
	for(i=0;i<l;i++)
		n[i] = str[l-i-1];
	printf("%s", n);
}

C++: #include<iostream>
using namespace std;
int main(void){
    char str[21]="";
    cin >> str;
    for(int i=20; i>=0; i--){
        if(str[i]!='\0') cout << str[i];
    }
    cout << endl;
    return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;

int main() {
	string s;
	cin >> s;
	reverse(s.begin(), s.end());
	cout << s << "\n";
	return 0;
}

C++: #include<iostream>
#include<string>

using namespace std;

int main()
{
	string str;
	
	cin >> str ;
	
	int i=str.size()-1;
	
	for(;i>=0;i--)
		cout << str[i] ;
	
	cout << endl;
	
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
//ranker
using namespace std;

using ll = long long;
using ull = unsigned long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using pii = pair<int, int>;
using pis = pair<int, string>;
using psi = pair<string, int>;
using D = double;
using P = complex<D>;
template <typename T> using PQ = priority_queue<T>;
template <typename T> using minPQ = priority_queue<T, vector<T>, greater<T>>;


int main()
{
    string str;

    cin >> str;
    reverse( str.begin() , str.end() );
    cout << str << endl;

    return 0;
}

C++: #include<iostream>
#include<cstring>
using namespace std;
int main()
{
  char s[21];
  cin >> s;
  int len = strlen(s);
  for(int i = len;i >= 0;i--){
    cout << s[i];
  }
  cout << endl;
}

C++: #include <stdio.h>
int main(void){
    char s[21],*p;
    while(~scanf("%s",s)){
        for(p=s;*p++;);
        for(p--;s<=p;p--)printf("%c",*p);
        puts("");
    }
    return 0;
}

C++: #include<iostream>

using namespace std;

#define rep(i, n) for (int i = 0; i < int(n); ++i)

int main() {
  string str;
  cin >> str;
  rep (i, str.size()) {
    cout << str[str.size() - i - 1];
  }
  cout << endl;
}

C++: #include <bits/stdc++.h>
using namespace std;

int main(){
  string str;
  cin >> str;
  reverse(str.begin(), str.end());
  cout << str << endl;
}

C++: #include <bits/stdc++.h>
using namespace std;

#define iota(i,n,b,s) for(int i=int(b);i!=int((b)+(s)*(n));i+=(s))
#define range(i,n,m) iota(i,(((n)>(m))?((n)-(m)+1):((m)-(n)+1)),(n),((n)>(m)?-1:1))
#define rep(i,n) iota(i,(n),0,1)

#define INF (1e9)
#define EPS (1e-9)
#define cons(a,b) (make_pair(a,b))
#define car(a) (a.first)
#define cdr(a) (a.second)
#define cadr(a) (car(cdr(a)))
#define cddr(a) (cdr(cdr(a)))
#define all(a) a.begin(), a.end()
#define trace(var) cerr<<">>> "<<#var<<" = "<<var<<endl;

typedef long long Integer;
typedef double Real;

template<class S, class T>
ostream& operator<<(ostream& os, pair<S,T> p) {
  os << '(' << car(p) << ", " << cdr(p) << ')';
  return os;
}

template<class T>
ostream& operator<<(ostream& os, vector<T> v) {
  os << v[0];
  for (int i=1, len=v.size(); i<len; ++i) os << ' ' << v[i];
  return os;
}

int dx[] = { -1, 0, 1, 0 };
int dy[] = {  0, -1, 0, 1 };

int main() {

  string s;cin>>s;reverse(all(s));cout<<s<<'\n';

  return 0;
}

C++: #include <stdio.h>
#include <iostream>
#include <string.h>


using namespace std;

int main() {
int kazu;
char rin[21];
scanf("%s",rin);
	
	kazu = strlen(rin);
	
	for(int i = kazu-1; i >= 0; i--) {
	 cout << rin[i];
	}
	
	cout << "\n";
	
    return 0;
}

C++: #include <iostream>
#include<string>
using namespace std;

int main()
{
	string s;
	cin >> s;
	for(int i=s.size()-1;i>=0;i--)
	{
		cout << s[i];
	}
	cout << endl;

	return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;

int main(void)
{
	 string str;
	 cin >> str;
	 reverse(str.begin(), str.end());
	 cout << str << endl;
}

C++: #include<iostream>
#include<string>
using namespace std;

int main(){
	string str;
	cin >> str;
	for(int i = str.size(); i >= 0; i--){
		cout << str[i];
	}
	cout << endl;
}