#include <bits/stdc++.h>
#define int long long
using namespace std;
const int O = 3e5 + 5;
const int inf = 1e18;
int n, k, a[O], lazy[O * 4];
struct Node{
int sum, l, r, w, pref, suf, lsuf, rpref;
} tree[O * 4], rtree[O * 4];
Node Merg(Node x, Node y){
Node root; root.w = -inf;
root.sum = x.sum + y.sum;
root.pref = x.pref + (x.pref == x.sum ? max(0ll, y.pref) : 0);
root.rpref = (x.pref == x.sum && y.pref > 0) ? y.rpref : x.rpref;
root.suf = y.suf + (y.suf == y.sum ? max(0ll, x.suf) : 0);
root.lsuf = (y.suf == y.sum && x.suf > 0) ? x.lsuf : y.lsuf;
if (x.w > root.w){
root.w = x.w;
root.l = x.l;
root.r = x.r;
}
if (y.w > root.w){
root.w = y.w;
root.l = y.l;
root.r = y.r;
}
if (x.suf + y.pref >= root.w){
root.w = x.suf + y.pref;
root.l = x.lsuf;
root.r = y.rpref;
}
return root;
}
void Push(int id){
int &x = lazy[id];
if (x == 0) return;
for (int i = 2 * id; i <= 2 * id + 1; ++ i){
swap(tree[i], rtree[i]);
lazy[i] ^= x;
}
x = 0; return;
}
void Build(int id, int l, int r){
if (l == r){
tree[id] = {a[l], r, l, a[r], a[l], a[r], l, r};
rtree[id] = {-a[r], l, r, -a[l], -a[r], -a[l], r, l};
return;
}
int mid = (l + r) / 2;
Build(id << 1, l, mid);
Build(id << 1 | 1, mid + 1, r);
tree[id] = Merg(tree[id << 1], tree[id << 1 | 1]);
rtree[id] = Merg(rtree[id << 1], rtree[id << 1 | 1]);
}
void Update(int id, int l, int r, int u, int v){
if (l > v || r < u) return;
if (u <= l && r <= v){
swap(tree[id], rtree[id]);
lazy[id] ^= 1;
return;
}
int mid = (l + r) / 2; Push(id);
Update(id << 1, l, mid, u, v);
Update(id << 1 | 1, mid + 1, r, u, v);
tree[id] = Merg(tree[id << 1], tree[id << 1 | 1]);
rtree[id] = Merg(rtree[id << 1], rtree[id << 1 | 1]);
}
main(){
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin >> n >> k;
for (int i = 1; i <= n; ++ i) cin >> a[i];
Build(1, 1, n);
int res = 0;
for (int i = 1; i <= k; ++ i){
if (tree[1].w < 0) break;
res += tree[1].w;
Update(1, 1, n, tree[1].l, tree[1].r);
}
cout << res;
return 0;
}
