#include<bits/stdc++.h>
using namespace std;
 #define ll long long
int rem(int i,int j){
    if(i%j) return 1;
    else return 0;
}

int main(){

        ll t;
        cin>>t;
        while(t--){
            ll n;
            ll k;
            cin>>n>>k;
            vector<ll>a(n);
            ll sum=0;
            for(ll i=0;i<n;i++){
                cin>>a[i];
                sum+=a[i];
            }



            if(sum<=k){
                cout<<0<<endl;
            }

            else{
                ll diff=sum-k;
                if(diff>1){
                sort(a.begin(),a.end());

                ll minm=a[0];
                ll steps=INT_MAX;
                ll decr=0;
                for(ll i=n-1;i>=0;i--){
                    // cout<<"element "<<a[i]<<endl;
                    decr+=a[i]-minm;
                    // cout<<"decr "<<decr<<endl;
                    // cout<<"2nd steps "<<n-i<<endl;
                    if(decr>=diff){
                        steps=min(steps,n-i);
                    }
                    else{
                        if(i!=0){
                        ll extra=(diff-decr)/(n-i+1)+rem((diff-decr),(n-i+1));
                        steps=min(steps,n-i+extra);

                        }
                        else{
                            steps=min(steps,diff);
                        }
                    }
                    // cout<<"steps "<<steps<<endl;
                }

                cout<<steps<<endl;
            }

            else{
                cout<<1<<endl;

            }
            }
        }

    return 0;
}