#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
int main() {
int n;
char buf[11000];
cin >> n;
getchar();
//cin.getline(buf, 11000);
fgets(buf, 11000, stdin);
int len = strlen(buf);
for (int i=0;i<len;i+=2) {
char a=buf[i],b = buf[i+1];
if(a==' '){
printf(" ");
i++;
a = buf[i];
b = buf[i+1];
}
//cout << b;
if('a'<=b && b<='z') {
char temp = (a-'a')+(b-'a')-n;
if(temp <0) temp += 26;
printf("%c", ((temp)%26)+'a');
}
else if(b==' '){
printf(" ");
}
}
cout << endl;
return 0;
}
