#include <iostream>
#define int long long
using namespace std;
const int NMAX=3e5+5;
int n, k, v[NMAX];
struct dyn{int val, cnt;}dp[2][NMAX], ans;
dyn maxx(dyn a, dyn b)
{
if(a.val==b.val)
return ((a.cnt>b.cnt)?a:b);
return ((a.val>b.val)?a:b);
}
void solve(int lambda)
{
dp[0][0]={0, 0};
dp[1][0]={-lambda, 1};
for(int i=1;i<=n;i++)
{
dp[0][i]=maxx(dp[0][i-1], dp[1][i-1]);
dp[1][i]=maxx({dp[0][i-1].val+v[i]-lambda, dp[0][i-1].cnt+1}, {dp[1][i-1].val+v[i], dp[1][i-1].cnt});
}
ans=maxx(dp[0][n], dp[1][n]);
}
int caut_bin()
{
int r=0, pas=(1LL<<62);
while(pas)
{
solve(r+pas);
if(ans.cnt>=k)
r+=pas;
pas/=2;
}
solve(r);
return ans.val+r*k;
}
signed main()
{
cin>>n>>k;
for(int i=1;i<=n;i++)
cin>>v[i];
cout<<caut_bin();
return 0;
}
