#include "bits/stdc++.h"
using namespace std;
template<typename T>
using V = vector<T>;
using ll = long long;
using pi = pair<ll, ll>;
#define ckmax(a,b) a= max(a,b)
inline std::pair<long long, long long> operator-(const std::pair<long long, long long>& p1, const std::pair<long long, long long>& p2) {
return {p1.first - p2.first, p1.second - p2.second};
}
pi solve(V<ll>&arr, ll k, ll p) {
V<V<pi>> dp(arr.size() + 1, V<pi>(2, {-1e18,0}));
dp[0][0] = {0,0};
for (ll i = 1; i <= arr.size(); ++i) {
dp[i][0] = {0,0};
for (ll l = 0; l < 2; ++l) {
ckmax(dp[i][l], max(dp[i - 1][1] - make_pair(p,-1), dp[i - 1][1]));
if (l == 0) ckmax(dp[i][l], dp[i - 1][0]);
ckmax(dp[i][l], dp[i - 1][0] - make_pair(p,-1));
if (l == 1) dp[i][l].first += arr[i - 1];
}
}
return max(dp[arr.size()][0], dp[arr.size()][1]);
}
int main() {
ll n, k; cin >> n >> k;
V<ll> arr(n);
for (ll i = 0; i < n; ++i) {
cin >> arr[i];
}
ll l = 0, r = 1e18;
int iter = 0;
while (r > l) {
ll mid = l + (r - l + 1) / 2;
if (solve(arr, k, mid).second >= k)
l = mid;
else
r = mid - 1;
iter++;
if (iter > 62) exit(5);
}
cout << solve(arr,k,l).first + l * k << "\n";
}
