#include<bits/stdc++.h>
#define maxn 300005
#define fi first
#define se second
using namespace std;
using ii = pair<int, int>;
using li = pair<int64_t, int>;
int n, k;
int a[maxn];
li dp[maxn][2];
li solve_lambda(int64_t x) {
dp[0][1] = {LLONG_MIN/2, 0};
for (int i = 1; i <= n; i++) {
dp[i][0] = max(dp[i-1][0], dp[i-1][1]);
dp[i][1] = max(li{dp[i-1][1].fi+a[i], dp[i-1][1].se}, li{dp[i-1][0].fi+a[i]-x, dp[i-1][0].se+1});
}
return max(dp[n][0], dp[n][1]);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> k;
for (int i = 1; i <= n; i++) cin >> a[i];
int64_t lo = 0, hi = 100000000000000000LL;
while (hi-lo>1) {
int64_t mid = (lo+hi)>>1LL;
if (solve_lambda(mid).se >= k) lo = mid;
else hi = mid;
}
cout << solve_lambda(lo).fi + k*lo;
}
