#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/trie_policy.hpp>
#define pb push_back
#define mp make_pair
#define taskname "A"
#define int long long
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> ii;
const int maxn = 3e5 + 5;
struct Node{
int sum , pre , suf , res;
int ppre , psuf , pl , pr;
Node(){};
Node(int sum , int pre , int suf , int res,int ppre , int psuf , int pl , int pr)
:sum(sum),pre(pre),suf(suf),res(res),ppre(ppre),psuf(psuf),pl(pl),pr(pr){};
Node operator + (const Node other){
if(ppre == -1)return other;
if(other.ppre == -1)return (*this);
Node ans;
if(res < other.res)ans = other;
else ans = (*this);
ans.sum = sum + other.sum;
if(pre > sum + other.pre){
ans.pre = pre;
ans.ppre = ppre;
}else{
ans.pre = sum + other.pre;
ans.ppre = other.ppre;
}
if(other.suf > other.sum + suf){
ans.suf = other.suf;
ans.psuf = other.psuf;
}else{
ans.suf = other.sum + suf;
ans.psuf = psuf;
}
if(ans.res < suf + other.pre){
ans.res = suf + other.pre;
ans.pl = psuf;
ans.pr = other.ppre;
}
return ans;
}
}s[maxn * 4] , rs[maxn * 4];
int n , k;
bool lz[maxn * 4];
int a[maxn];
void Build(int x , int l , int r){
if(l == r){
s[x] = Node(a[l],a[l],a[l],a[l],l,l,l,l);
rs[x] = Node(-a[l],-a[l],-a[l],-a[l],l,l,l,l);
return;
}
int mid = l + r >> 1;
Build(x*2,l,mid);
Build(x*2+1,mid+1,r);
s[x] = s[x * 2] + s[x * 2 + 1];
rs[x] = rs[x * 2] + rs[x * 2 + 1];
}
void Push(int x , bool key){
if(lz[x])swap(s[x],rs[x]);
if(key){
lz[x * 2] ^= lz[x];
lz[x * 2 + 1] ^= lz[x];
}
lz[x] = 0;
}
void update(int x , int l , int r , int pos ,int val){
Push(x,l!=r);
if(l == r){
a[l] = val;
s[x] = Node(a[l],a[l],a[l],a[l],l,l,l,l);
rs[x] = Node(-a[l],-a[l],-a[l],-a[l],l,l,l,l);
lz[x] = 0;
return;
}
int mid = l + r >> 1;
if(pos <= mid)update(x*2,l,mid,pos,val);
else update(x*2+1,mid+1,r,pos,val);
s[x] = s[x * 2] + s[x * 2 + 1];
rs[x] = rs[x * 2] + rs[x * 2 + 1];
}
void Rev(int x , int l , int r , int L , int R){
Push(x,l!=r);
if(L > r || l > R)return;
if(L <= l && r <= R){
lz[x] ^= 1;
Push(x,l!=r);
return;
}
int mid = l + r >> 1;
Rev(x*2,l,mid,L,R);Rev(x*2+1,mid+1,r,L,R);
s[x] = s[x * 2] + s[x * 2 + 1];
rs[x] = rs[x * 2] + rs[x * 2 + 1];
}
Node Query(int x , int l , int r , int L , int R){
Push(x,l!=r);
if(L > r || l > R)return Node(-1,-1,-1,-1,-1,-1,-1,-1);
if(L <= l && r <= R)return s[x];
int mid = l + r >> 1;
return Query(x*2,l,mid,L,R)+Query(x*2+1,mid+1,r,L,R);
}
int32_t main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
if(fopen(taskname".INP","r")){
freopen(taskname".INP", "r",stdin);
freopen(taskname".OUT", "w",stdout);
}
cin >> n >> k;
for(int i = 1 ; i <= n ; ++i){
cin >> a[i];
}
Build(1,1,n);
ll res = 0;
while(k--){
if(s[1].res <= 0)break;
res += s[1].res;
Rev(1,1,n,s[1].pl,s[1].pr);
}
cout << res;
}
