#include <iostream>
#include <string>
#include <map>
 
using namespace std;
 
string n_to_letter{"ABCDEFGHIJKLMNOPQRSTUVWXYZ"};
map<char, int> letter_to_n;
string key;
 
void build_letter_to_n()
{
  for (int i = 0; i < n_to_letter.size(); ++i)
    letter_to_n[n_to_letter[i]] = i;
}
 
string cipher(string in)
{
  string out;
  for (int i = 0; i < in.size(); ++i)
  {
    int n = letter_to_n[in[i]];
    int k = letter_to_n[key[i % key.size()]];
    n = (n + k) % n_to_letter.size();
    out += n_to_letter[n];
  }
 
  return out;
}
 
int main()
{
  cin >> n_to_letter; // alphabet
 
  build_letter_to_n();
 
  cin >> key;
 
  string in;
  cin >> in;
 
  cout << cipher(in);
 
  return 0;
}
 
 

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

IUFCQ0RFRkdISUpLTE1OT1BRUlNUVVZXWFlaClNFQ1JFVApIRUxMT1dPUkxEIQ==

!ABCDEFGHIJKLMNOPQRSTUVWXYZ
SECRET
HELLOWORLD!