HDU:Good Numbers

#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <algorithm>
#define ll long long
using namespace std;
ll Sum(ll val)
{
    ll sum=0;
    while(val)
    {
        sum+=val%10;
        val/=10;
    }
    return sum;
}
ll solve(ll val)
{
    if(val<0) return 0;
    ll cnt=0;
    for(ll i=val/10*10; i<=val; ++i)
        if(Sum(i)%10==0)
            cnt++;
    return val/10+cnt;
}
int main()
{
    int T,kase=0;
    scanf("%d",&T);
    while(T--)
    {
        ll a,b;
        scanf("%I64d%I64d",&a,&b);
        printf("Case #%d: %I64d\n",++kase,solve(b)-solve(a-1));
    }
    return 0;
}