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 <iostream>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <algorithm>
#include <functional>

using namespace std;

int gcd( int, int );

int main()
{
	char str[21];

	scanf("%s", str );
	
	vector<char> v( str, str + strlen( str ) );
	reverse( v.begin(), v.end() );

	for ( unsigned int i = 0; i < v.size(); i++ )
	{
		printf("%c", v[i] );
	}

	return 0;
}

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

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

C++: #include<iostream>
#include <cstdio>
#include<cmath>
#include<vector>
#include<algorithm>

using namespace std;

////Nayeem Shahriar Joy,Applied Physics &Electronic Engineering,University of Rajshahi.

int main()

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

C++: #include<iostream>
#include<string.h>
using namespace std;
int main(){
	char bun[25] = {};
	int len;
	cin >> bun;
	len=strlen(bun);
	for(int i=len-1;i>0;i--){
		cout<<bun[i];
	}
	cout<<endl;
	return 0;
}

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

using _i64 = int64_t;
using _u64 = uint64_t;
using _f64 = double;

#define _for(i, start, end) for(_i64 i = (_i64)start; i < (_i64)end; ++i)
#define _rep(i, number) _for(i, 0, number)
#define _foreach(e, data) for(auto& e : data)
#define _all(data) data.begin(), data.end()

template<typename type>
_i64 _size(const type& data) { return static_cast<_i64>(data.size()); }
template<typename type, size_t size>
_i64 _size(const type (&)[size]) { return static_cast<_i64>(size); }

enum _flag : bool { able = true, disable = false };

struct _time {
    _time(_flag flag) { check = flag; if(!check) { return; } gettime(start); }
    ~_time() {
        if(!check) { return; }; gettime(end);
        _i64 elapse = chrono::duration_cast<chrono::milliseconds>(end - start).count();
        cout << endl << "Time: " << elapse << " ms" << endl;
    }
    private:
    using _timer = chrono::time_point<chrono::system_clock>;
    _timer start, end; bool check;
    void gettime(_timer& time) { time = chrono::system_clock::now(); }
};

struct _ini { _ini() { ios::sync_with_stdio(false); cin.tie(nullptr); } } _ini;

int main() {
    {
        _time time(disable);
        string str; cin >> str;
        reverse(_all(str));
        cout << str << endl;
    }
    return 0;
}

C++: #include <iostream>

using namespace std;

int main(){
  string s;
  cin >> s;
  s = string(s.rbegin(),s.rend());
  cout << s << endl;
  return 0;
}

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

using namespace std;

int main ()
{
	string str;
	getline(cin, str);
	for (string::reverse_iterator rit=str.rbegin(); rit!=str.rend(); ++rit)
		cout << *rit;
	cout << endl;
	return 0;
}

C++: #include<iostream>

using namespace std;

int main()
{
        string input;
        int num = 0;
        int i = 0;
        int count = 0;
        char temp[1];

        cin >> input;
        num = input.size();
        char str[num]; //= input.toCharArray(); 

        sprintf(str,"%s",input.c_str());

        if(num % 2 == 0)
        {
                count = num / 2;
        }
        else
        {
                count = (num - 1) / 2;
        }

        for(i = 0;i < count;i++)
        {
                temp[0] = str[i];
                str[i] = str[num -  1 - i];
                str[num - 1 - i] = temp[0];
        }

        string output = string(str);
        cout << output << endl;

}

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

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

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

C++: /* -*- coding:utf-8 -*- */

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

int main()
{
  string s;
  cin >> s;
  string::reverse_iterator it = s.rbegin();

  while(it != s.rend()) {
    cout << *it;
    it++;
  }
  cout << endl;

  return 0;
}

C++: #include<cstdio>

int main(){
	char str[20];
	char c;
	int i = -1;
	scanf("%c", &c);
	while(c - 10){
		i++;
		str[i] = c;
		scanf("%c", &c);
	}
	for(; i >= 0; i--){
		printf("%c", str[i]);
	}
	printf("\n");
	return 0;
}

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

using namespace std;

int main()
{
    char s[20];
    int n,T;
    while(cin>>s){
       n=strlen(s);
       
       for(int i=0;i<(n/2);i++){
          T=s[i];
          s[i]=s[n-i-1];
          s[n-i-1]=T;        
       }             
       cout<<s<<endl; 
    }
    return 0;
}

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

int main(int argc, char *argv[]) {
	char rcv[21];
	char out[21];
	fscanf(stdin, "%s\n", rcv);
	int cnt = 0;
	for (int i = 0; i < 21; i++) {
		if (rcv[i] == '\0') {
			for (int j = i-1; j !=-1; j--) {
				out[cnt] = rcv[j];
				cnt++;
			}
			out[cnt] = '\0';
			break;
		}
	}
	printf("%s\n", out);
	
	return 0;
}

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

using namespace std;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  
  string str;
  cin >> str;
  reverse(str.begin(), str.end());
  cout << str << endl;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
int main()
{
  std::string s;
  while (std::cin >> s) {
    std::reverse(s.begin(), s.end());
    std::cout << s << std::endl;
  }
  return 0;
}

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<stdio.h>
#include<string.h>

void main()
{
 char str[20],temp;
 int i,j=0;
 gets(str);
 i=0;
 j=strlen(str)-1;

 while(i<j)
     {
     temp=str[i];
     str[i]=str[j];
     str[j]=temp;
     i++;
     j--;
     }

 printf("%s",str);
 return 0;
}

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 << endl;
  }
  return 0;

}

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

C++: #include <stdio.h>
#include <string.h>
int main()
{
   char a[20];
   gets(a);
   strrev(a);
   printf("%s\n",a);
   return 0;
}

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

int main(){
    char str[21],res[21];
    int n;
    scanf("%s",str);
    n = strlen(str);

    for(int i = 0; i < n; i++){
        res[n - i - 1] = str[i];
    }
    res[n] = '\0';
    printf("%s\n",res);
    return 0;
}

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

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

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

using namespace std;

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

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

using namespace std;

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

}