#include<bits/stdc++.h>
using  namespace  std ;
#define ll long long

int  main () {
    double n,s;cin>>n>>s;
    double sum=0;
    string a;
    for(int i=0;i<n;i++) {
        cin >> a;
       int d=(a[0]-'0');
       if(a.size()>1){
            sum+=d;
            sum++;
        }else{
            sum+=d;
        }
    }
    sum-=s;

    if(sum<0)cout<<"0\n";
    else
        cout<<::ceil(sum/s)<<endl;

        //cout<<((int)sum/s!=sum/s?(int)sum/s+1:sum/s)<<endl;
}