Go: package main

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

var sc = bufio.NewScanner(os.Stdin)

func main() {
	sc.Scan()
	s := sc.Text()
	l := len(s)
	r := make([]rune, l)
	for i, c := range s {
		r[l-i-1] = c
	}
	fmt.Println(string(r))
}

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

using namespace std;

int main(){
    int size;
    char str[21];
    cin >> setw(21) >> str;
    size = strlen(str);
    for(int i=size-1;0<=i;i--){
        cout << str[i];
    }
    cout << endl;
    return 0;
}

C++: #include<iostream>
#include<string>
using namespace std;
int main() {
  string s;
  cin>>s;
  for(int i=s.size();i>=0;i--){
    cout<<s[i];
  }
  cout<<endl;
}

C++: #include<bits/stdc++.h>
#define loop(i, a, b) for(int i = a; i < b; i++) 
#define rep(i, a) loop(i, 0, a)
using namespace std;
const int MOD = 1000000007;
const int inf = 1e8;
using vi = vector <int>;
using vvi = vector <vi>;
using vc = vector <char>;
using vvc = vector <vc>;
using vs = vector <string>;
using vvs = vector <vs>;
//g++ -std==c++14
//setprecision(10)
string str;

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

C++: #include<iostream>
using namespace std;
int main(){
  char str[20];
  cin>>str;
  for(int i=20;i>0;i--)
    cout<<str[i-1];
  cout<<endl;
  return 0;
}

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-1];
	}
	cout << endl;
	return 0;
}

C++: #include<iostream>
using namespace std;
	
int main()
{
	char change[19];
	cout<<"??????????????\????????????????????????\n";
	cin>>change[19];
	int j=strlen(change);
	j-=1;
	for(int i=j;i>=0;i--){
	cout<<"change[i];
	}
	return 0;
}

C++: // 2011/05/30 Tazoe

#include <iostream>
#include <string>
using namespace std;

int main()
{
	string str;
	cin >> str;

	for(int i=str.size()-1; i>=0; i--)
		cout << str[i];
	cout << endl;

	return 0;
}

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

int main()
{
  char s[21],tmp;
  int len;

  while(cin >> s){
    len = 0;
    while(s[len++]);
    for(int i=0;i<(len-1)/2;i++){
      tmp = s[i];
      s[i] = s[len-i-2];
      s[len-i-2] = tmp;
    }
    s[len-1] = '\0';

    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;


}

C++: #include<iostream>
#include<cstring>
using namespace std;
int main(void){
  string str;
  int len;

  while(cin >> str){
  len=str.length();

  for(int i=len;i>=0;i--){
    cout << str[i] ;

  }
  cout<<str[len+1];
  cout << endl;
  }
  return 0;

}

C++: #include<stdio.h>
#include<stdlib.h>
int main(void){
  char a,b,i,j;
  char rarara[1000];
  char papapa[1000]; 
 gets(rarara);
 for(i=0;rarara[i]!=NULL;i++){};
 a=i;
  for(i=0;i<a;i++)
    papapa[i]=rarara[a-i-1];
  papapa[a]=NULL;
  printf("%s\n",papapa);
  return;
}

C++: #include <cstdio>
#include <stack>

using namespace std;

int main()
{
	char str[21];
	stack<char> stk;

	fgets( str, sizeof( str ) - 1, stdin );

	for ( int i = 0; str[i] != '\n'; i++ )
	{
		stk.push( str[i] );
	}

	while ( !stk.empty() )
	{
		putchar( stk.top() );
		stk.pop();
	}	

	return 0;
}

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

int main(){
  int i=0;
  char str[25], rts[25];
  cin >> str ;
  while(1){
    if(str[i]=='\0'){
      break;
    }
    i++;
  }

  
  for(int j=0;i>0;j++){
    rts[j]=str[i-1];
    i--;
  }
  cout << rts << endl;
  return 0;
}

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

int main(){
    std::string str;
    std::cin >> str;
    const int size = str.size();
    for(int i = 0; i < size; ++i){
        if(i != size - 1){
            std::cout << str.back();
        }else{
            std::cout << str.back() << std::endl;
        }
        str.erase(str.size() - 1, 1);
    }
    return 0;
}

C++: #include <cstdio>
#include <cstring>
 
int main(){
 char str[21];
 scanf("%s",str);
 for(int i = strlen(str) - 1;i >= 0;i--){printf("%c",str[i]);}
 return 0;
}

C++: #include <stdio.h>

int main(){

	int i;
	char str[20] = {};
	
	scanf("%s", str);
	
	for (i = 0; i < 20; i++){
		if (str[19 - i] >0){ printf("%c", str[19-i]); }
	}

	return 0;
}

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

int main(){
	std::string st;
	
	std::cin >> st;
	
	while(!(st.empty())){
		std::cout << st.back();
		st.pop_back();
	}
	
	return 0;
}

C++: #include<iostream>
#include<string>
using namespace std;
int main(){
	string a;
	while(1){
		cin >> a;
		if(a.length() < 20)
			break;
	}
	for(int i=a.length()-1; i>-1; i--){
		cout << a[i];
		}
	return 0;
}

C++: #include <cstdio>
#include <string>
using namespace std;
int main() {
  char str[20];
  scanf("%s", str);
  int len = strlen(str);
  for (int i = len-1; i >= 0; i--) {
    printf("%c", str[i]);
  }
  printf("\n");
  return 0;
}

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

int main()
{
    char ch[20];
	int i=0;
	while(cin >> ch[i]){
		i++;
	}
	for(int j=i-1 ; j>=0 ; j--){
		cout<<ch[j];
	}
	return 0;
}

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

std::string reverse_str(std::string str);

int main()
{
	std::string str;
	while (std::cin >> str)
	{
		str = reverse_str(str);
		std::cout << str << std::endl;
	}
	return 0;
}

std::string reverse_str(std::string str)
{
	std::string str_ans;
	for (unsigned long i = 1; i <= str.size(); ++i)
	{
		decltype(str)::iterator it = std::prev(end(str), i);
		str_ans += *it;
	}
	return str_ans;
}

C++: #include<iostream>
#include<cstdio>
#include<utility>
#include<climits>
#include<cmath>
using namespace std;

int main()
{
	int i, j;

	char str[20] = {};
	for (i = 0; cin >> str[i]; i++)
	{}

	for (j = i - 1; j >= 0; j--)
	{
		cout << str[j] ;
	}

	cout << endl;
	return 0;
}

C++: #include <iostream>
#include <string>
using namespace std;
int main(){
	string s;
	cin>>s;
	for(int i=0;i<20;i++){
		cout<<s[20-1-i];
	}
    return 0;
}

C++: #include<iostream>
#include<cstring>
using namespace std;
int main()
{
    char str[25];
    cin>>str;
    char rev[25];
    for(int i=0;i<strlen(str);i++)
        rev[i]=str[strlen(str)-i-1];
    rev[strlen(str)]='\0';
    cout<<rev<<endl;
}

C++: #include<stdio.h>
#include<string.h>
int main(){
	char a[100];
	scanf("%s",&a);
	for(int i=strlen(a)-1;i>=0;i--){
		printf("%c",a[i]);
	}
	return 0;
}

C++: #include<stdio.h>
#include<string.h>
int main(void)
{
	int i,len;
	char c[21];
	scanf("%s",c);
	len=strlen(c);
	for(i=len-1;i>=0;i--){
		printf("%c",c[i]);
	}
	printf("\n");
	return 0;
}

C++: #define _USE_MATH_DEFINES
#include <iostream> 
#include <math.h>
#include <vector>
#include <algorithm>
#include <string>
using namespace std; 
int main(){
	string str;
	cin >> str;
	reverse(str.begin(), str.end());
	cout << str << endl;
	return 0;
}

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

using namespace std;

int main()
{
	char str[22];

	fgets( str, sizeof( str ) - 1, stdin );

	for ( int i = strlen( str ) - 2; 0 <= i; i-- )
	{
		putchar( str[i] );
	}

	return 0;
}

C++: #include <stdio.h>
#include <string.h>
int main()
{
   char a[20];
   gets(a);
   strrev(a);
   printf("%s\n",a);

   return 0;
}

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

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

C++: #include<iostream>
using namespace std;
int main(){
  int i; int l  = 0;
	   char str[21]; char str1[21];
  cin >> str;
  for(i=0;str[i] != '\0';){i++;}
    for(int k = i-1;k >=0 ;l++, k--){
      cout << str[k];    
  }
  cout << endl;
}

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

int main(){ 
    string in,buf; 
    int f=0,b;

    cin >> in;
    b = in.size()-1;

    while(b-f >= 1){
        buf = in[f];
        in[f] = in[b];
        in[b] = buf[0]; 
        f++;    
        b--;    
    }

    cout << in << endl;
    return 0;
}