自己看

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll n,m;
ll a[1000010];
int main(){
	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);
	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
	std::cout.tie(nullptr);
	cin>>n>>m;
    for(ll i=1;i<=n;i++){
        cin>>a[i];
    }
    sort(a+1,a+1+n);
    ll l=0,r=a[n];
    ll sum=0;
    while(l<=r){
        ll ans=0;
        ll mid=l+r>>1;
        for(ll i=1;i<=n;i++){
            if(a[i]>mid){
                ans+=a[i]-mid;
            }
        }
        if(ans>=m) sum=mid,l=mid+1;
        else r=mid-1;
    }
    cout<<sum<<endl;
	//fclose(stdin);
	//fclose(stdout);
	return 0;
}
//coder::by::M91