题解

#include<bits/stdc++.h>
using namespace std;
int a,b,ans;
int main()
{
    cin>>a>>b;
    for(int i=a;i<=b;i++)
    {
        ans+=i%10;
        ans+=i/10%10;
        ans+=i/100%10;
        ans+=i/1000;
	}
    cout<<ans;
    return 0;
}