#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
typedef long long ll;
typedef long double db;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef pair<db,db> pdb;
typedef tuple<int,int,int> tii;
typedef tuple<ll,ll,ll> tll;
typedef tuple<int,int,int,int> ti4;
typedef vector<vector<ll>> mat;
const ll mod=1e9+7,inf=1e18;
const int N=3e5+5,M=2e5+5,K=1e7+5;
int n,k;
ll a[N],ans;
struct SEG{
struct node{
tll Lmx,Rmx,Sum,Mx;
tll Lmx2,Rmx2,Sum2,Mx2;
void Swap(){
swap(Lmx,Lmx2); swap(Rmx,Rmx2); swap(Sum,Sum2); swap(Mx,Mx2);
}
node operator +(node n1){
node n;
n.Lmx=max(Lmx,{get<0>(Sum)+get<0>(n1.Lmx),get<1>(Sum),get<2>(n1.Lmx)});
n.Rmx=max(n1.Rmx,{get<0>(Rmx)+get<0>(n1.Sum),get<1>(Rmx),get<2>(n1.Sum)});
n.Sum={get<0>(Sum)+get<0>(n1.Sum),get<1>(Sum),get<2>(n1.Sum)};
n.Mx=max({Mx,n1.Mx,{get<0>(Rmx)+get<0>(n1.Lmx),get<1>(Rmx),get<2>(n1.Lmx)}});
n.Lmx2=max(Lmx2,{get<0>(Sum2)+get<0>(n1.Lmx2),get<1>(Sum2),get<2>(n1.Lmx2)});
n.Rmx2=max(n1.Rmx2,{get<0>(Rmx2)+get<0>(n1.Sum2),get<1>(Rmx2),get<2>(n1.Sum2)});
n.Sum2={get<0>(Sum2)+get<0>(n1.Sum2),get<1>(Sum2),get<2>(n1.Sum2)};
n.Mx2=max({Mx2,n1.Mx2,{get<0>(Rmx2)+get<0>(n1.Lmx2),get<1>(Rmx2),get<2>(n1.Lmx2)}});
return n;
}
}tree[4*N]; bool lazy[4*N];
void pd(int nd,int l,int r){
if(lazy[nd]) tree[nd].Swap();
if(l!=r){
lazy[nd<<1]^=lazy[nd];
lazy[nd<<1|1]^=lazy[nd];
}
lazy[nd]=0;
}
void init(int nd,int l,int r){
if(l==r){
tll t1={a[l],l,l},t2={-a[l],l,l};
tree[nd]={t1,t1,t1,t1,t2,t2,t2,t2};
return;
}
int m=(l+r)>>1;
init(nd<<1,l,m); init(nd<<1|1,m+1,r);
tree[nd]=tree[nd<<1]+tree[nd<<1|1];
}
void upd(int nd,int l,int r,int s,int e){
pd(nd,l,r);
if(r<s||e<l) return;
if(s<=l&&r<=e){
lazy[nd]=1; pd(nd,l,r); return;
}
int m=(l+r)>>1;
upd(nd<<1,l,m,s,e); upd(nd<<1|1,m+1,r,s,e);
tree[nd]=tree[nd<<1]+tree[nd<<1|1];
}
}Solver;
int main(){
ios::sync_with_stdio(false); cin.tie(0);
cin>>n>>k;
for(int i=1;i<=n;i++) cin>>a[i];
Solver.init(1,1,n);
for(int i=1;i<=k;i++){
if(get<0>(Solver.tree[1].Mx)<=0) break;
ans+=get<0>(Solver.tree[1].Mx);
Solver.upd(1,1,n,get<1>(Solver.tree[1].Mx),get<2>(Solver.tree[1].Mx));
}
cout<<ans;
return 0;
}
