题解

#include<iostream>
using namespace std;
int main(){
    int a,b,sum=0;
    cin>>a>>b;
    for(int i=a;i<=b;i++){
        int x=i;
        while(x!=0){
            sum+=x%10;
            x/=10;
        }
    }
    cout<<sum;
    return 0;
}