#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ar array
#define rep(i, n) for(int i = 0; i<(int)n; ++i)
const int mxN = 3e5+5, M = 1e9+7;
int n, k;
ll a[mxN];
pair<long double, int> dp[2][mxN];
ll f(long double lambda){
dp[0][0] = {0, 0};
dp[1][0] = {a[0]-lambda, 1};
for(int i = 1; i<n; ++i){
dp[0][i] = max(dp[0][i-1], dp[1][i-1]);
dp[1][i] = max(make_pair(dp[0][i-1].first+a[i]-lambda, dp[0][i-1].second+1), make_pair(dp[1][i-1].first+a[i], dp[1][i-1].second));
}
return max(dp[0][n-1], dp[1][n-1]).second;
}
void solve(){
cin >> n >> k;
rep(i, n) cin >> a[i];
long double l = 0, r = 1e9;
rep(_, 70){
long double m = (l+r+1)/2;
if(f(m) < k){
r = m;
}else{
l = m;
}
}
long double lambda = l;
f(lambda);
cout << (ll)round(lambda * k + max(dp[0][n-1], dp[1][n-1]).first);
}
int main(){
#ifdef _DEBUG
// freopen("input.txt", "r", stdin);
// freopen("output.txt", "w", stdout);
#endif
std::ios_base::sync_with_stdio(false); std::cin.tie(0); std::cout.tie(0);
solve();
}
