#include <stdio.h>
#include <string.h>
char a[100];
int p[25]={2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97},b[100];
int main()
{
    int maxn=0,minn=0,flag=0;
    for (int i = 0; i < 100; i++)
    {
        b[i]=0;
    }
    scanf("%s",a);
    int c=strlen(a);
for (int i = 0; i < c; i++)
{
    b[a[i]-'a']++;
}
for (int i = 0; i < 26; i++)
{
    if (b[i]>maxn)
    {
        maxn=b[i];
    }
    if (b[i]<=minn)
    {
        minn=b[i];
    }
}
for (int i = 0; i < 25; i++)
{
if (p[i]==maxn-minn)
{
    flag=1;
    break;
}
}
if (flag)
{
    printf("lucky word\n");
    printf("%d",maxn-minn);
}
else
printf("no anwser\n");
printf("0");
return 0;
}