#include<bits/stdc++.h>
using namespace std;
#define ll long long int
const int N = 3e5 + 5, mod = 1e9 + 7;
ll arr[N];
ll dp[2][N], cnt[2][N];
int32_t main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, k; cin >> n >> k;
for(int i = 1; i <= n; i++) cin >> arr[i];
ll mn = -1e16;
ll ans = mn;
ll lo = mn, hi = -mn;
while(lo <= hi) {
ll mi = (lo + hi) / 2;
dp[1][0] = mn;
cnt[1][0] = 1;
for(int i = 1; i <= n; i++) {
dp[0][i] = max(dp[0][i - 1], dp[1][i - 1]);
if(dp[0][i - 1] > dp[1][i - 1])
cnt[0][i] = cnt[0][i - 1];
else
cnt[0][i] = cnt[1][i - 1];
dp[1][i] = max(dp[0][i - 1] - mi, dp[1][i - 1]) + arr[i];
if(dp[0][i - 1] - mi > dp[1][i - 1])
cnt[1][i] = cnt[0][i - 1] + 1;
else cnt[1][i] = cnt[1][i - 1];
}
int part;
ll cost;
if(dp[0][n] >= dp[1][n]) {
part = cnt[0][n];
cost = dp[0][n] + part * mi;
}
else {
part = cnt[1][n];
cost = dp[1][n] + part * mi;
}
if(part <= k) ans = max(ans, cost), hi = mi - 1;
else lo = mi + 1;
}
cout << ans << "\n";
return 0;
}
