#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; i++)
#define FORD(i, b, a) for (int i = (b), _a = (a); i >= _a; i--)
#define REP(i, n) for (int i = 0, _n = (n); i < _n; i++)
#define FORE(i, v) for (__typeof((v).begin()) i = (v).begin(); i != (v).end(); i++)
#define ALL(v) (v).begin(), (v).end()
#define IS_INF(x) (std::isinf(x))
#define IS_NAN(x) (std::isnan(x))
#define fi first
#define se second
#define int long long
#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)
#define div ___div
#define prev ___prev
#define next ___next
#define left ___leftc
#define right ___right
#define TIME (1.0 * clock() / CLOCKS_PER_SEC)
#define __Im_sogood__ main()
#define __builtin_popcount __builtin_popcountll
using namespace std;
const int MAXN = 3e5 + 5;
const int INF = 1e18;
int n, k, a[MAXN]; pair<int, int> f[MAXN][2];
pair<int, int> calc(int lambda) {
FOR(i, 1, n) REP(j, 2) f[i][j] = make_pair(0, 0);
f[1][0] = {0, 0}; f[1][1] = {a[1] - lambda, 1};
FOR(i, 2, n) {
f[i][0] = max(f[i - 1][0], f[i - 1][1]);
f[i][1] = max(make_pair(f[i - 1][0].first + a[i] - lambda, f[i - 1][0].second + 1),
make_pair(f[i - 1][1].first + a[i], f[i - 1][1].second));
}
return max(f[n][0], f[n][1]);
}
void solve() {
cin >> n >> k; FOR(i, 1, n) cin >> a[i];
int lo = 0, hi = INF, ans_lambda = 0; while(lo <= hi) {
int mid = (lo + hi) >> 1; pair<int, int> ans = calc(mid);
if(ans.second > k) { lo = mid + 1; } else {
ans_lambda = mid; hi = mid - 1;
}
}
pair<int, int> answer = calc(ans_lambda);
cout << answer.first + answer.second * ans_lambda;
}
__Im_sogood__{
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
solve();
cerr << "Time elapsed: " << TIME << " s.\n";
return 0;
}
