Go: package main

import (
        "fmt"
)

func main () {
        var str string
        fmt.Scanf("%s", &str)
        show(len(str)-1, str)
}

func show(n int, str string) {
        if n == 0 {
                fmt.Printf("%s\n", string(str[n]))
        } else {
                fmt.Printf("%s", string(str[n]))
                show(n-1, str)
        }
}

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

int main() {
	const int size = 21;
	char str[size];
	std::scanf("%s", &str);

	for (int i = size - 1; i >= 0; i--)
		if (48 <= str[i] && str[i] <= 57)
			std::cout << str[i];
		else if(97 <= str[i] && str[i] <= 122)
			std::cout << str[i];

	std::cout << std::endl;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
typedef long long LL;
int main(){
	string A;
	cin>>A;
	string B;
	REP(i,A.size()){
	    B.push_back(A[A.size()-1-i]);
	}
        cout<<B<<endl;
	return(0);
}

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

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

int main(){
    std::string str;
    while(std::cin >> str){
        for(auto it=str.rbegin(); it!=str.rend(); ++it)
            std::cout << *it;
    }
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>	// require sort next_permutation count __gcd reverse etc.
#include <cstdlib>	// require abs exit atof atoi 
#include <cstdio>		// require scanf printf
#include <functional>
#include <numeric>	// require accumulate
#include <cmath>		// require fabs
#include <climits>
#include <limits>
#include <cfloat>
#include <iomanip>	// require setw
#include <sstream>	// require stringstream 
#include <cstring>	// require memset
#include <cctype>		// require tolower, toupper
#include <fstream>	// require freopen
#include <ctime>		// require srand
#define rep(i,n) for(int i=0;i<(n);i++)
#define ALL(A) A.begin(), A.end()

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

int main()
{
//	cut here before submit 
//	freopen ("testcase.RS", "r", stdin );
	string str = "";
	cin >> str;
	reverse (ALL (str ) );
	cout << str << 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<<endl;

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

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

	return 0;
}

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

#define N 20
using namespace std;

int main() {
    char str[N];
    cin >> str;
    reverse(str,str+strlen(str));
    printf("%s\n",str);
    return 0;
}

C++: // In the name of Allah
#include <stdio.h>
#include <string.h>

int main(){
	char st[21];
	scanf("%s",&st);
	strrev(st);
	printf("%s",st);
	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-1];
	}
	cout << endl;
	return 0;
}

C++: #include<iostream>
#include<iomanip>
#include<map>
#include<set>
#include<string>
#include<algorithm>
#include<cmath>
#include<vector>
#include<queue>
#include<stack>
#include<cstring>
#include<sstream>
using namespace std;
 
#define P(p) cout<<(p)<<endl
#define rep(i,m,n) for(int i = (m); i < (int)(n); i++)
#define rrep(i,m,n) for(int i=(int)(m); i>=(int)(n); i--)
#define vsort(v) sort(v.begin(), v.end());
#define rvsort(v) sort(v.begin(), v.end(),greater<int>());
#define YES cout<<"YES"<< endl
#define NO cout<<"NO"<<endl
#define Yes cout<<"Yes"<<endl
#define No cout<<"No"<<endl  
#define yes cout<<"yes"<<endl
#define no cout<<"no"<<endl
#define ret return
#define lb(v,n) lower_bound(v.begin(),v.end(),n)
#define ub(v,n) upper_bound(v.begin(),v.end(),n)
#define mae(v) max_element(v.begin(),v.end())
#define mie(v) min_element(v.begin(),v.end())

////////////////////////////////////////////////////////////

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

	rrep(i,s.size()  - 1, 0 )
		cout << s[i];
	cout << endl;
	ret 0;
}

C++: /*
C++ ???????????????????????????????????¬??????
??????AOJ-ITP1??????????????????
*/
#define _USE_MATH_DEFINES

#include <iostream> // ?¨??????\??????
#include <fstream>  // ??????????????\??????
#include <string>   // ???????????¢???
#include <vector>   // ???????????????
#include <cmath>    // ??°??????
#include <iomanip>  // stream???????????¢???
#include <algorithm>// max??¢??°??????

using std::cin;
using std::cout;
using std::endl;
using std::string;
using std::vector;        // ????´???°????????????????????????
using std::fixed;         // ???????????????????¨???????????????????????????????
using std::setprecision;  // ?????°????°???°?????\???????????°????????????????????¨????????\???

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

C++: #include<bits/stdc++.h>
int main()
{
	int i=21;
	char st[21];
	memset(st,false,sizeof(st));
	scanf("%s",&st);
	for(;i--;){
		if(st[i]){
			if(isalnum(st[i]) || isalpha(st[i])){
				printf("%c",st[i]);
			}
	}
	printf("\n");
	return 0;
}
}

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

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

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

int main(void){
	int i;
	int len;
	char str[20],rts[20] = {};

	scanf("%s",str);
	len = strlen(str);
	for(i = 0;i < len;i++){
		rts[i] = str[len - (i+1)];
	}
	printf("%s\n",rts);
	return 0;
}