#include<bits/stdc++.h>
using namespace std;
#define int long long
int n , k;
const int INF = 1e15;
vector<int> a;
pair<int , int> better(pair<int , int> opt1 , pair<int , int> opt2){
if(opt1.first != opt2.first){
return (opt1.first > opt2.first) ? opt1 : opt2;
}
else{
return (opt1.second >= opt2.second) ? opt1 : opt2;
}
}
pair<int , int> check(int lambda){
pair<int , int> dp1 = {-INF , 0}, dp0 = {0 , 0};
for(int i = 0 ; i < n ; i++){
pair<int , int> opt1 = {(dp1.first == -INF) ? -INF : dp1.first + a[i] , dp1.second};
pair<int , int> opt2 = {dp0.first + a[i] - lambda , dp0.second + 1};
dp1 = better(opt1 , opt2);
dp0 = better(dp1 , dp0);
}
return dp0;
}
int solve(){
int l = -1e15;
int r = 1e15;
int ans = 0;
while(l < r){
int m = l + ((r-l+1) / 2);
if(check(m).second >= k){
l = m;
ans = m;
}
else{
r = m -1;
}
}
return l;
}
signed main(){
cin>>n >> k;
a.resize(n);
for(int i = 0 ; i < n ;i++)cin>>a[i];
int ans = solve();
pair<int , int> fans = check(ans);
cout << max(0LL , fans.first + (ans * k));
}
