#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N = (int)3e5 + 1;
int n, k;
ll a[N];
pair<ll, ll> solve(ll x) {
vector<vector<pair<ll, ll>>> dp(2, vector<pair<ll, ll>> (n, {0, 0}));
dp[0][0] = {0, 0}, dp[1][0] = {-x + a[0], 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[1][i-1].first + a[i], dp[1][i-1].second),
make_pair(dp[0][i-1].first + a[i] - x, dp[0][i-1].second + 1)
);
}
return max(dp[0][n-1], dp[1][n-1]);
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n >> k;
for (int i = 0; i < n; i++) cin >> a[i];
ll l = 0, r = 1e18;
while (l < r) {
ll mid = (l + r + 1) / 2;
int opt = solve(mid).second;
if (opt >= k) l = mid;
else r = mid - 1;
}
pair<ll, ll> mx = solve(l);
cout << mx.first + mx.second * l;
}
