#include<stdio.h>
int main()
{
int i=0,j=0,k=0,x=0,rem=0,sum=0,count=0;
scanf("%d%d%d",&i,&j,&k);
for(i;i<=j;i++)
{
x=i;
while(x!=0)
{
rem=x%10;
sum=(sum*10)+rem;
x=x/10;
}
if(abs(i-sum)%k==0)
count=count+1;
sum=0;
}
printf("%d",count);
return 0;
}