include iostream include string include queue include cmath include se

#include <iostream>
#include <string>
#include <queue>
#include <cmath>
#include <set>
#include <iomanip>
using namespace std;


inline long long gCount(long long curr, long long maxim)
{
    long long answer = 0;
    if(curr < 10)
    {
        answer = (min(maxim, 10ll) - curr);  
        return answer;
    }
    if(curr < 100)
    {
        answer = 2 * (min(maxim, 100ll) - curr);
        return answer;
    }
    if(curr < 1000)
    {
        answer = 3 * (min(maxim, 1000ll) - curr);  
        return answer;
    }
    if(curr < 10000)
    {
        answer = 4 * (min(maxim, 10000ll) - curr);
        return answer;
    }
    if(curr < 100000)
    {
        answer = 5 * (min(maxim, 100000ll) - curr); 
        return answer;
    }
    if(curr < 1000000)
    {
        answer = 6 * (min(maxim, 1000000ll) - curr); 
        return answer;
    }
    if(curr < 10000000)
    {
        answer = 7 * (min(maxim, 10000000ll) - curr); 
        return answer;
    }
    if(curr < 100000000)
    {
        answer = 8 * (min(maxim, 100000000ll) - curr);
        return answer;
    }
    if(curr < 1000000000ll)
    {
        answer = 8 * (min(maxim, 1000000ll) - curr); 
        return answer;
    }
    return answer;
}


int main()
{
 int n = 0;
 int a = 0;


 cin >> n >> a;

 long long answer = 0;

 int maxim = 1;

 int ta = a;

 while(ta > 0)
 {
    maxim *= 10;
    ta /= 10;
 }

 int i = 0;

 maxim = min(maxim, a + n);
 for(i = a; i <= n + a; )
 {
     answer += gCount(i, maxim);
     i = maxim;
     if(maxim == min(maxim * 10, n + a))
         break;
     maxim = min(maxim * 10, n + a);
 }


 cout << answer;
return 0;
}