#include<stdio.h>
#include<string.h>

int main(){
	char a[100],j;
	int i,k,count=0,max=1,min=100,sum,flag,sub;
	for(i=0;;i++)
	{
		scanf("%c",&j);
		if(j=='\n')
		break;
		else
		{
		 a[i]=j;
		 count++; }
	}
	for(i=0;i<count-1;i++)
	{
		flag=0;
		if(i>0)
		{ for(j=i-1;j>=0;j--)
		  {
		  	if(a[j]==a[i])
		  	{ flag=1;
			  break;
		    }
	      }     
		}
		if(flag) continue;
		sum=0;
		for(j=i+1;j<count;j++)
		{   if(a[j]==a[i])
			sum++;	     }
		if(sum>=max)
		max=sum;
		if(sum<=min)
		min=sum;
	}
	sub=max-min;
	flag=1;
    if(sub==0||sub==1)
	flag=0;
	for(i=2;i<=((sub+1)/2);i++)
	{
		if(sub%i==0&&sub!=2)
	   {	flag=0;
	        break;
	   }
	}
	if(flag)
	printf("lucky word!\n%d",sub);
	else
    printf("no answer!\n0");
	 
}