#include <stdio.h>
#include <algorithm>
#include <vector>
#include <queue>
#define N_MAX 1000000
#include <stdlib.h>
using namespace std;
typedef pair <int,int> ppair;
priority_queue <ppair,vector<ppair>,greater<ppair> > PQ;
int N, K, Ans;
int M, Block[N_MAX+1], Size[N_MAX+1];
int Left[N_MAX+1], Right[N_MAX+1];
int main(void) {
int i, inp, t1, t2, h1, h2;
scanf("%d %d",&N,&K);
Block[0]=-1;
for(i=1 ; i<=N ; i++) {
scanf("%d",&inp);
if(Block[M]==inp) Size[M]++;
else Block[++M]=inp, Size[M]=1;
}
if(M>1 && Block[1]==Block[M]) Size[1]+=Size[M--];
if(M==1) {
printf("0");
return 0;
}
if(Block[M]>Block[1]) Left [1]=M;
if(Block[1]<Block[2]) Right[1]=2;
if(Left[1] && Right[1]) PQ.push(make_pair(Size[1],1));
for(i=2 ; i<=M-1 ; i++) {
if(Block[i-1]>Block[i ]) Left [i]=i-1;
if(Block[i ]<Block[i+1]) Right[i]=i+1;
if(Left[i] && Right[i]) PQ.push(make_pair(Size[i],i));
}
if(Block[M-1]>Block[M]) Left [M]=M-1;
if(Block[M ]<Block[1]) Right[M]=1;
if(Left[M] && Right[M]) PQ.push(make_pair(Size[M],M));
while(!PQ.empty()) {
t1=PQ.top().first, t2=PQ.top().second, PQ.pop();
h1=K/t1;
h2=min(Block[Left[t2]],Block[Right[t2]])-Block[t2];
if(h1<h2) {
Ans+=h1<<1;
break;
}
else {
Ans+=h2<<1;
K-=t1*h2;
if(Block[Left[t2]]<Block[Right[t2]]) {
Size [Left[t2]]+=Size [t2];
Right[Left[t2]] =Right[t2];
if(Left[Left[t2]]) PQ.push(make_pair(Size[Left[t2]],Left[t2]));
}
else if(Block[Left[t2]]>Block[Right[t2]]) {
Size[Right[t2]]+=Size[t2];
Left[Right[t2]] =Left[t2];
if(Right[Right[t2]]) PQ.push(make_pair(Size[Right[t2]],Right[t2]));
}
else {
inp=Size[Left[t2]];
Size [Left[t2]]+=Size[t2]+Size[Right[t2]];
Right[Left[t2]] =Right[Right[t2]];
Size[Right[t2]]+=Size[t2]+inp;
Left[Right[t2]] =Left[Left[t2]];
if(Left[Left[t2]] && Right[Left[t2]]) PQ.push(make_pair(Size[Left[t2]],Left[t2]));
}
}
}
printf("%d",Ans);
return 0;
}
