#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int64_t oo = 1e18;
#define int long long
//#define float long double
#define quickly ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define FOR(I, L, R) for(int I(L) ; I <= (int)R ; ++I)
#define FOD(I, R, L) for(int I(R) ; I >= (int)L ; --I)
#define FOA(I, A) for(auto I : A)
#define print(A,L,R) FOR(OK, L, R){if(A[OK]<=-oo||A[OK]>=oo)cout<<"- ";else cout<<A[OK]<<' ';}cout<<'\n';
#define prints(A) FOA(OK, A){cout<<OK<<' ';}cout << '\n';
#define printz(A,L,R) FOR(OK, 0, L){FOR(KO, 0, R){if(A[OK][KO]>-oo&&A[OK][KO]<oo)cout<<A[OK][KO]<<' ';else cout << "- ";} cout << '\n';}cout << '\n';
#define fs first
#define sd second
#define th second.second
#define ii pair<int,int>
#define iii pair<int, ii>
#define all(A) A.begin(), A.end()
const int N = 3e5 + 5;
const int mod = 1e9 + 7;
int n, k, mx;
int a[N];
ii dp[2][N];
ii calc(int lambda){
dp[1][0] = {-oo, -oo};
FOR(i, 1, n){
dp[0][i] = max(dp[1][i - 1], dp[0][i - 1]);
dp[1][i] = max(ii(dp[1][i - 1].fs + a[i], dp[1][i - 1].sd),
ii(dp[0][i - 1].fs + a[i] - lambda, dp[0][i - 1].sd + 1));
}
return max(dp[0][n], dp[1][n]);
}
int Alien(){
int l = 0, r = mx * n;
int ans = 0;
while(l <= r){
int mid = (l + r) >> 1;
if(calc(mid).sd >= k){
l = mid + 1;
ans = mid;
}
else{
r = mid - 1;
}
}
return calc(ans).fs + ans * k;
}
signed main(){ quickly
cin >> n >> k;
FOR(i, 1, n){
cin >> a[i];
mx = max(a[i], mx);
}
cout << Alien();
}
