// Source: https://usaco.guide/general/io
#include <bits/stdc++.h>
#define f first
#define s second
#define mp make_pair
#define int long long
using namespace std;
int a[300001];
pair<int, int> solve(int l, int n) {
pair<int, int> dp[n][2];
dp[0][0] = {0, 0};
dp[0][1] = {a[0]-l, 1};
for (int i = 1; i < n; i++) {
dp[i][0] = max(dp[i-1][0], dp[i-1][1]);
dp[i][1] = max(
mp(dp[i-1][0].f+a[i]-l, dp[i-1][0].s+1),
mp(dp[i-1][1].f+a[i], dp[i-1][0].s)
);
}
return max(dp[n-1][0], dp[n-1][1]);
}
signed main() {
int n, k; cin >> n >> k;
for (int i = 0; i < n; i++) {
cin >> a[i];
}
int low = 0;
int high = 1e9;
int mid = low + (high - low) / 2;
while (low < high) {
mid = low + (high - low) / 2;
pair<int, int> res = solve(mid, n);
if (res.s <= k) {
high = mid;
}
else {
low = mid + 1;
}
}
cout << solve(low, n).f+low*k;
}
