#include <iostream>
#define ll long long
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define fi first
#define se second
#define inf 1e18
using namespace std;
typedef pair<ll, int> li;
const int N = 3e5 + 9;
int n, k;
ll pre[N], a[N], ans;
li dp[N];
void maximize(li &a, li b){
if (a.fi < b.fi) a = b;
if (a.fi == b.fi) a = max(a, b);
}
li calc(ll cost){
//FOR(i, 1, n) dp[i] = {pre[i] - cost, 1};
li best = {0, 0};
for (int i = 1; i <= n; ++i) {
dp[i] = dp[i-1];
maximize(dp[i], {pre[i] + best.fi - cost, best.se + 1});
maximize(best, {dp[i].fi - pre[i], dp[i].se});
}
return dp[n];
}
int main(){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
// freopen("nhap.inp", "r", stdin);
// freopen("xuat.out", "w", stdout);
cin >> n >> k;
FOR(i, 1, n) cin >> a[i], pre[i] = pre[i-1] + a[i];
ll lo = -1e15, hi = 1e15;
while (lo <= hi) {
ll mid = lo + hi >> 1;
li tmp = calc(mid);
if (tmp.se <= k) {
ans = max(ans, tmp.fi + tmp.se*mid);
hi = mid - 1;
} else lo = mid + 1;
}
cout << ans;
return 0;
}
