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++: #include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <queue>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <complex>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <fstream>
#include <stdio.h>

using namespace std;

//conversion
//------------------------------------------
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<double> VEC;
typedef vector<VEC> MAT;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<int, PII> TIII;
typedef long long LL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;
//container util

//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())
#define MT(a,b,c) MP(a, MP(b, c))
#define T1 first
#define T2 second.first
#define T3 second.second.first
#define T4 second.second.second

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define EPS 1.0e-9

int main(){
	string str;
	cin>>str;
	reverse(ALL(str));
	cout<<str<<endl;
	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", n);
}

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

using namespace std;
static const int MAXV = 21;

int main() {
  char A[MAXV]={};
  cin >> A;
  int i=0;
  for(;i<MAXV;i++) {
    //printf("%c", A[i]);
    if (A[i] == 0) break;
  }
  i--;
  for(;i!=-1;i--) {
    printf("%c", A[i]);
  }
}

C++: #include<bits/stdc++.h>
using namespace std;
int main(){
	char ch[21];
	cin>>ch;
	int n=strlen(ch);
	char bch[n];
	int t=n-1;
	for(int a=0;a<n;a++){
		bch[t]=ch[a];
		t--;
	}
	for(int b=0;b<n;b++){
		printf("%c",bch[b]);
	}
	printf("\n");
}

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

#define MAX 256

int main(void){

	char str[21];
	int c = 0;
	scanf("%s", &str);
	for (int i = 0; str[i] != '\0'; i++){
		c++;
	}
	for (int i = c; i >= 0; i--){
		printf("%c", str[i]);
	}
	printf("\n");
	
	return 0;
}

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

using namespace std;

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

C++: #include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include <random>
#include <cmath>
#include <iomanip>
#include <climits>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <map>
#include <deque>
#include <map>
#include <set>
#include <unordered_set>
#include <queue>
#include <stack>
#include <list>
#include <unordered_map>
#include <bitset>
#include <sstream>
#include <new>
#include <typeinfo>
#include <iterator>
#include <cassert>

typedef long long ll;
typedef unsigned long long ull;
constexpr ll mop = 1000000007;
constexpr ll mop2 = 998244353;

using namespace std;

constexpr ll NOT_SPECIFIED_VALUE_MIN = INT64_MIN;
constexpr ll NOT_SPECIFIED_VALUE_MAX = INT64_MAX;

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

C++: #include<iostream>
#include<string>
using namespace std;
int main()
{
	string s;
	char temp;
	int i, len;
	while (cin >> s)
	{
		len = s.length();
		for (i = 0; i < len / 2; i++)
		{
			temp = s[i];
			s[i] = s[len - 1 - i];
			s[len - 1 - i] = temp;
		}
		cout << s << endl;
	}
	return 0;
}

C++: #include <stdio.h>
#include <string.h>
int main(void){
    char a[30];
    int n,i;
    scanf("%s",a);
    n=strlen(a);
    for(i=n-1;i>=0;i--){
        printf("%c",a[i]);
    }
    
}

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

#define rep(i,n) for(int i=0;i<n;i++)
#define REP(i,s,n) for(int i=(s);i<=(n);i++)
#define repr(i,n) for(int i=n-1;i>=0;i--)
#define REPR(i,s,n) for(int i=(s);i>=(n);i--)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define Eunique(v) v.erase(unique(all(v)),v.end())
#define Eback(s) s.erase(s.end()-1,s.end())
#define rev(v) reverse(all(v))
#define minvec(v) *min_element(all(v))
#define maxvec(v) *max_element(all(v))
#define sumvec(v) accumulate(all(v),0LL)
#define mapmin(v) v.rbegin()->first
#define mapmax(v) v.begin()->first
#define pb push_back
#define pf push_front
#define m_p make_pair
#define DOUBLE fixed << setprecision(15)
#define OK cerr<<"OK\n"
#define OK1 cerr<<"OK1\n"
#define OK2 cerr<<"OK2\n"
#define SIZE(s) (int)s.size()
#define INF ((1LL<<62)-(1LL<<31))
#define zero(x,n) setw(x) << setfill('0') << n
#define endl '\n'

typedef long long ll;

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<long long> vll;
typedef vector<vll> vvll;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<char> vc;
typedef vector<vc> vvc;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<string> vs;

typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
typedef vector<pair<int,int>> vpii;
typedef vector<pair<ll,ll>> vpll;

const double pi = acos(-1.0);
const ll mod=1000000007;
const ll mod2=998244353;

template<class A, class B>
ostream& operator<<(ostream& ost, const pair<A, B>&p) {
	ost << "{" << p.first << ", " << p.second << "} ";
	return ost;
}

template<class T>
ostream& operator<<(ostream& ost, const vector<T>&v) {
	ost << "{";
	for (int i = 0; i<(int)v.size(); i++) {
		if (i)ost << " ";
		ost << v[i];
	}
	ost << "} \n";
	return ost;
}

template<class A, class B>
ostream& operator<<(ostream& ost, const map<A, B>&v) {
	ost << "{";
	for (auto p:v) {
		ost << "{" << p.first << ", " << p.second << "} ";
	}
	ost << "} ";
	return ost;
}

template<class T>
inline bool chmax(T& a, T b){if(a<b){a=b;return true;} return false;}

template<class T>
inline bool chmin(T& a, T b){if(a>b){a=b;return true;} return false;}

void YES(bool b) {cout << ((b)?"YES\n":"NO\n");}
void Yes(bool b) {cout << ((b)?"Yes\n":"No\n");}
void yes(bool b) {cout << ((b)?"yes\n":"no\n");}
void Yay(bool b) {cout << ((b)?"Yay!\n":":(\n");}

ll powmod(ll a,ll b){ll c=1; while(b>0){ if(b&1){ c=a*c%mod; } a=a*a%mod; b>>=1; } return c;}
ll nCrmod(ll n,ll r){ll x=1,y=1; rep(i,r){x=x*(n-i)%mod; y=y*(i+1)%mod;} return x*powmod(y,mod-2)%mod;}
ll gcd(ll x, ll y) {return __gcd(x,y);}
ll lcm(ll x, ll y) {return x/__gcd(x,y)*y;}

int main()
{
	string s;
	cin >> s;
	reverse(all(s));
	cout << s << endl;
	return 0;
}

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

using namespace std;

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

C++: #include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;

void main()
{
	char k[25];
	scanf("%s",k);
	reverse(k,k+strlen(k));
	printf("%s",k);
}

C++: #include<bits/stdc++.h>

using namespace std;

int main(){
  char str[21];
  cin >> str;
  for(int i=strlen(str)-1;i>=0;i--){
    printf("%c",str[i]);
  }
  cout << endl;
  return 0;
}