C++ :

#include <iostream>
using namespace std;
int main() {
    int k,a,b;
    cin>>k>>a>>b;
    int s=0;
    for (int i=a;i<=b;i++) {
        if (i%10==k||i%k==0) {
            s+=i;
   		}
	}
    cout<<s;
    return 0;
}