439A Devu, the Singer and Churu, the Joker codeforces solution in cpp

 

439A Devu, the Singer and Churu, the Joker codeforces solution in cpp

by ujjal roy

#include<bits/stdc++.h>

using namespace std;

main()

{

    int n,d,i,sum=0,a,r;

    cin>>n>>d;

    for(i=1;i<=n;i++)

    {

        cin>>a;

        sum+=a;

    }

    if(d<(n-1)*10+sum) cout<<"-1"<<endl;

    else

    {

        r=d-sum;

        cout<<r/5<<endl;

    }

    return 0;

}