#include<bits/stdc++.h>
#define int long long
#define pb push_back
#define fi first
#define se second
#define pii pair<int,int>
#define vc vector<vector<int>>
using namespace std;
const int MOD=1e9+7;
const int N=3e5+5;
int a[N];
pii solve(int n,int lb){
pii dp[n][2];
for(int i=0;i<n;++i){
dp[i][1]=dp[i][0]={-1e18,0};
}
dp[0][0]={0,0};
dp[0][1]={a[0]-lb,1};
for(int i=1;i<n;++i){
dp[i][0]=max(dp[i-1][0],dp[i-1][1]);
pii dp1={dp[i-1][0].fi+a[i]-lb,dp[i-1][0].se+1};
pii dp2={dp[i-1][1].fi+a[i],dp[i-1][1].se};
dp[i][1]=max(dp1,dp2);
}
return max(dp[n-1][1],dp[n-1][0]);
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n,k;
cin>>n>>k;
for(int i=0;i<n;++i)cin>>a[i];
int l=-1e14;
int r=1e14;
int ld=0;
while(l<=r){
int mid=(l+r)/2;
pii tmp=solve(n,mid);
if(tmp.se>=k){
ld=mid;
l=mid+1;
}
else {
r=mid-1;
}
}
pii res=solve(n,ld);
cout<<res.fi+ld*k;
}
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