1D：数位五五

 #include<bits/stdc++.h>

using namespace std;


bool test_five(int num){
    stack<int> s;
    int temp=num;
    while(temp){
        s.push(temp%10);
        temp=temp/10;
    }

    temp=0;
    while(!s.empty()){
        temp+=s.top();
        s.pop();
    }
    if(temp%5==0)
        return true;
    else
        return false;
}



int fun(int lo,int hi){
    int count=0;
    for(int i=lo;i<=hi;i++){
        if(test_five(i))
            count++;

    }
    return count;
}


int main(){

    int a,b,ans;
    cin>>a>>b;
    ans=fun(a,b);
    cout<<ans<<endl;

    return 0;
}