#pragma GCC optimize("O3", "unroll-loops") // "Ofast"
#pragma GCC target("avx2", "bmi", "bmi2", "lzcnt", "popcnt")
#include <bits/stdc++.h>
//#define int long long
#define vt vector
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define ff first
#define ss second
#define dbg(x) cerr << #x << " = " << x << '\n'
#define bit(x, i) ((x) >> (i) & 1)
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vvt = vt< vt<int> >;
const int N = 1e6 + 5, mod = 1e9 + 7, B = 500;
const ll inf = 1e18 + 7, LIM = (1ll << 60);
const double eps = 1e-6;
int n, k;
ll a[N], p[N];
pll dp[N][2];
ll calc (ll x) {
for (int i = 1; i <= n; i++) {
dp[i][0] = max(dp[i - 1][0], dp[i - 1][1]);
ll res = dp[i - 1][0].ff - x;
int kol = dp[i - 1][0].ss - 1;
dp[i][1] = max(dp[i - 1][1], {res, kol});
dp[i][1].ff += a[i];
dp[i][1] = max(dp[i][1], {a[i], 0});
}
return max(dp[n][0], dp[n][1]).ss * -1;
}
bool check (ll x) {
return (calc(x) < k);
}
void solve () {
cin >> n >> k;
for (int i = 1; i <= n; i++) cin >> a[i];
ll l = 0, r = inf, ans = 0;
while (l <= r) {
ll mid = l + r >> 1;
if (check(mid)) ans = mid, r = mid - 1;
else l = mid + 1;
}
calc(ans);
for (int i = 1; i <= n; i++) {
// cout << dp[i][0].ff - dp[i][0].ss * ans << ' ' << dp[i][0].ss << " " << dp[i][1].ff - dp[i][1].ss * ans << ' ' << dp[i][1].ss << '\n';
}
// cout << ans << ' ';
cout << max(dp[n][0], dp[n][1]).ff + ans * (k - 1);
cout << '\n';
}
bool testcases = 0;
signed main() {
#ifdef ONLINE_JUDGE
freopen(".in", "r", stdin);
freopen(".out", "w", stdout);
#endif
cin.tie(0) -> sync_with_stdio(0);
int test = 1;
if (testcases) cin >> test;
for (int cs = 1; cs <= test; cs++) {
solve();
}
}
