#include<bits/stdc++.h>
using namespace std;
#define ls(p) (p<<1)
#define rs(p) (ls(p)^1)
#define int long long
typedef pair<int,int> pii;
//typedef long long ll;
const int mod=1e9+7;
const double eps=1e-6;
const int INF=9223372036854775807;
const int N=1e5+5;
int a[N],s[N],n,k;
inline int read();
inline bool check(int x){
	int minn=1e18;
	for(int i=1;i<=n;++i){
		s[i]=s[i-1]+a[i]-x;
		if(i>=k){
			minn=min(minn,s[i-k]);
			if(s[i]>=minn){
				return true;
			}
		}
	}
	return false;
}
inline void solve(){
	n=read(),k=read();
	int l=1e18,r=0,ans=0;
	for(int i=1;i<=n;++i){
		a[i]=read();
		l=min(l,a[i]);
		r=max(r,a[i]);
	}
	while(l<=r){
		int mid=l+r>>1;
		if(check(mid))l=mid+1,ans=mid;
		else r=mid-1;
	}
	printf("%lld\n",ans);
}
signed main(){
	int T=1;
//	int T=read();
	while(T--)solve();
	return 0;
}
inline int read(){
	int x=0,f=1;char ch=getchar();
	while(ch<'0'||ch>'9'){
		if(ch=='-')f=-1;
		ch=getchar();
	}
	while(ch>='0'&&ch<='9')x=(x<<1)+(x<<3)+(ch^48),ch=getchar();
	return x*f;
}