#include <bits/stdc++.h>
using namespace std;
#define name "code"
#define MAXN 300005
#define pb push_back
#define pf push_front
#define ll long long
#define ii pair<int, int>
#define fs first
#define sc second
#define ill pair<int, ll>
#define lli pair<ll, int>
#define llll pair<ll, ll>
#define all(v) v.begin(),v.end()
#define uni(v) v.erase(unique(all(v)),v.end())
#define bit(n,i) (((n)>>(i))&1)
#define FOR(i,a,b) for (int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for (int i=(a),_b=(b); i>=_b; i--)
#define MASK(i) (1LL<<(i))
const int INF=1e9;
const int MOD=1e9+7;
void add(int &u, int v){
u+=v;
if (u>=MOD) u-=MOD;
}
void sub(int &u, int v){
u-=v;
if (u<0) u+=MOD;
}
void minimize(int &u, int v){
u=min(u,v);
}
void maximize(lli &u, lli v){
if (u.fs<v.fs) u=v;
else if (u.fs==v.fs){
if (u.sc>v.sc) u=v;
}
}
long long Rand(long long l, long long r){
ll tmp=0;
FOR(i,1,4) tmp=((tmp<<15)^(((1<<15)-1)&rand()));
return l+tmp%(r-l+1);
}
int n,k;
int a[MAXN];
lli dp[MAXN][2];
lli calc(ll lambda){
FOR(i,0,n) dp[i][0]=dp[i][1]={-(ll)1e18,0};
dp[0][0]={0,0};
FOR(i,1,n){
dp[i][0]=max(dp[i-1][0],dp[i-1][1]);
dp[i][1]=max((lli){dp[i-1][0].fs+1LL*a[i]-lambda,dp[i-1][0].sc+1},(lli){dp[i-1][1].fs+1LL*a[i],dp[i-1][1].sc});
}
return max(dp[n][0],dp[n][1]);
}
int main()
{
//freopen(name".inp","r",stdin);
//freopen(name".out","w",stdout);
ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
cin>>n>>k;
FOR(i,1,n) cin>>a[i];
long long l=0,r=(ll)1e18,res=0;
while (l<=r){
ll mid=(l+r)/2;
lli tmp=calc(mid);
if (tmp.sc>=k){
res=mid;
l=mid+1;
}
else r=mid-1;
}
cout<<calc(res).fs+1LL*k*res;
return 0;
}
