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 m=i;
        while (m != 0){
            sum += m % 10; 
            m /= 10;
        }
    }
    cout << sum;
    return 0 ;
}