#include <stdio.h>
int main()
{
	int n;
	scanf("%d",&n);
	n=n%26; 
	char c,a[50];
	c=getchar();
	while((c=getchar())!='\n')
	{
		if((c+n)<='z')
		printf("%c",c+n);
		else
		printf("%c",c+n-1-'z'+'a');
	}
}