10994 - Simple Addition

#include<iostream>
#include<cstdlib>
using namespace std;
typedef unsigned long long LONG;
LONG calc(long);
int main()
{
    LONG s;
    long long p,q;
    //freopen("in.txt","r",stdin);
    while(cin>>p>>q&&p>=0&&q>=0)
    {
        if(p)s=calc(q)-calc(p-1);
        else s=calc(q);
        cout<<s<<endl;
    }
    exit(0);
}
LONG calc(long n)
{
    LONG s1=0,s2=0,m;
    while(n)
    {
        m = n%10;
        n = n/10;
        s1 += ( ( LONG(m)*(m+1))/2);
        s2 +=LONG(n)*45;
    }
    return (s1 + s2);
}