easy

//#include<iostream>
#include<cstdio>
//#include<algorithm>
//#include<cmath>
//#include<string.h>

using namespace std;

int main()
{
int a,b,sum=0;
scanf("%d%d",&a,&b);
for(int i=a;i<=b;i++){
int c=i;
while(c){
sum+=c%10;
c/=10;
}
}
printf("%d",sum);
return 0;
}