#include<iostream>
#include<stack>
#include<map>
#include<vector>
#include<string>
#include<unordered_map>
#include <queue>
#include<cstring>
#include<limits.h>
#include <cassert>
#include <cstdint>
#include<cmath>
#include<set>
#include<algorithm>
#include <iomanip>
#include<numeric> //gcd(a,b)
#include<bitset>
using namespace std;
#define ll long long
#define f first
#define endl "\n"
#define s second
#define pii pair<int,int>
#define ppii pair<int,pii>
#define vi vector<int>
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define F(n) for(int i=0;i<n;i++)
#define lb lower_bound
#define ub upper_bound
#define fastio ios::sync_with_stdio(false);cin.tie(NULL);
#pragma GCC optimize ("03,unroll-loops")
using namespace std;
#define int long long
#define double long double
const int mod=1e9+7,mxn=3e5+5,lg=30,inf=1e16,minf=-1e18;
int v[mxn+10],mid;
pii dp[mxn+10][2];
int n,m;
int check(){
dp[0][0]={0,0};
dp[0][1]={minf,0};
for(int i=1;i<=n;i++){
dp[i][0]=max(dp[i-1][1],dp[i-1][0]);
dp[i][1]=max(make_pair(dp[i-1][1].f+v[i],dp[i-1][1].s),make_pair(dp[i-1][0].f+v[i]-mid,dp[i-1][0].s+1));
}
return max(dp[n][0],dp[n][1]).s;
}
int32_t main(){
fastio
cin>>n>>m;
for(int i=1;i<=n;i++)cin>>v[i];
int l=0,r=inf;
int ans=inf;
while(l<=r){
mid=l+(r-l)/2;
if(check()<=m)r=mid-1,ans=mid;
else l=mid+1;
}
mid=ans;
check();
cout<<(m*ans)+max(dp[n][0].f,dp[n][1].f);
/*
lambda increase
group decrease
*/
}
/*
*/
