#include <iostream>
#include <cstring>
#include <string>
using namespace std;
int main() {
int k, dlugosc;
string napis;
cin >> k >> napis;
dlugosc = napis.size();
char tab[dlugosc+1];
strcpy (tab, napis.c_str());
for (int i = 0; i < dlugosc; i++) {
cin >> tab[i];
if (tab[i] >= 'a' && tab[i] <= 'z') {
if ((tab[i]+k) > 'z')
tab[i] = 'a' + ((tab[i]+k)-'z');
else
tab[i] += k;
cout << tab[i];
}
else if (tab[i] >= 'a' && tab[i] <= 'z') {
if ((k>5 && (tab[i]+k)>'z') || (tab[i]+k)>'z')
tab[i] = '`' + ((tab[i]+k)-'z');
else
tab[i] += k;
cout << tab[i];
}
else
cout << tab[i];
}
}
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