#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair <ll,ll> pll;
typedef pair <int,int> pii;
typedef pair <int,pii> piii;
#define forr(_a,_b,_c) for(int _a = (_b); _a <= int (_c); ++_a)
#define ford(_a,_b,_c) for(int _a = (_b) + 1; _a --> int (_c);)
#define forf(_a,_b,_c) for(int _a = (_b); _a < int (_c); ++_a)
#define st first
#define nd second
#define pb push_back
#define mp make_pair
#define all(x) begin(x),end(x)
#define mask(i) (1LL << (i))
#define bit(x, i) (((x) >> (i)) & 1)
#define bp __builtin_popcountll
#define file "test"
template<class X, class Y>
bool minz(X &x, const Y &y) {
if (x > y) {
x = y;
return true;
} return false;
}
template<class X, class Y>
bool maxz(X &x, const Y &y) {
if (x < y) {
x = y;
return true;
} return false;
}
const int N = 5e5 + 5;
const ll oo = (ll) 1e16;
const ll mod = 1e9 + 7; // 998244353;
ll dp[N], cnt[N], a[N], n, k;
void calc (ll x){
ll mx = -x, mxcnt = 0;
forr (i, 1, n){
dp[i] = dp[i - 1];
cnt[i] = cnt[i - 1];
if (maxz(dp[i], mx + a[i])){
cnt[i] = mxcnt + 1;
}
if (maxz(mx, dp[i] - a[i] - x)){
mxcnt = cnt[i];
}
}
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
#ifdef hqm
freopen(file".inp", "r", stdin); freopen(file".out", "w", stdout);
#endif
cin >> n >> k;
forr (i, 1, n){
cin >> a[i];
a[i] += a[i - 1];
}
ll l = 0, r = mod * n;
while (l < r){
ll mid = (l + r + 1) >> 1;
calc(mid);
if (cnt[n] < k)
r = mid - 1;
else l = mid;
}
calc(l);
//cout << l << " " << dp[n] << " " << cnt[n] << endl;
cout << dp[n] + l * k;
return 0;
}
/*
*/
