b1:

#include<bits/stdc++.h>
using namespace std;
main()
{
    long long a, b, c;
    cin>>a;
    b=a/10;
    c=a%10;
    cout<<b+c;
}

b3:

#include<bits/stdc++.h>
using namespace std;
main()
{
    string s;
    cin>>s;
    reverse(s.begin(),s.end());
    cout<<s;
}

Program Tinh_Tuoi;

uses crt;

var

namsinh, namhientai,tuoi: Integer;

Begin

clrscr; write('Nhap nam sinh cua ban: ');

readln(namsinh);

namhientai:=2021;

writeln('Nam hien tai:', namhientai);

tuoi:=namhientai - namsinh;

writeln('ban sinh nam:', namsinh', => Hien tai ban', tuoi', tuoi!');

readln;

End.