package main
import(
	"fmt"
)
func main(){
	var(
		str [50]byte
		n int
	)
	fmt.Scanf("%d",&n)
	for i := 0;str[i] != '\n';i ++{
		fmt.Scanf("%c",&str[i])
		if str[i] == '\n'{
			break
		}
		for j := 0;j < n;j ++{
			if str[i] != 'z'{
				str[i] = str[i] + 1
			}else{
				str[i] = 'a'
			}
		}
	}
	for i := 0;i < len(str);i ++{
		fmt.Printf("%c",str[i])
	}
	fmt.Printf("\n")
}