include<stdio.h>

include<string.h>

int main() { int num,length,i; char code[50]; scanf("%d",&num); getchar(); gets(code); length=strlen(code); for(i=0;i<length;i++){ if((num+code[i])<='z') code[i]+=num; else code[i]='a'+num+code[i]-'z'-1; } for(i=0;i<length;i++) printf("%c",code[i]); return 0; }