#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pll pair<ll, ll>
#define f first
#define s second
int n, k, A[300005]; pll dp[300005][2];
pll better(pll a, pll b){
if (a.f == b.f) return (a.s < b.s ? a : b);
return (a.f > b.f ? a : b);
}
bool solve(ll lmb){
dp[0][0] = {0, 0}; dp[0][1] = {-1e18, 0};
for (int i = 1; i <= n; i++){
dp[i][0] = better(dp[i - 1][0], dp[i - 1][1]);
dp[i][1] = better({dp[i - 1][0].f + A[i] - lmb, dp[i - 1][1].s + 1},
{dp[i - 1][1].f + A[i], dp[i - 1][1].s});
}
return better(dp[n][0], dp[n][1]).s <= k;
}
int main(){
cin >> n >> k;
for (int i = 1; i <= n; i++) cin >> A[i];
ll L = 0, H = 1e18;
while (L < H){
ll M = (L + H) / 2;
solve(M) ? H = M : L = M + 1;
}
solve(L);
pll res = better(dp[n][0], dp[n][1]);
cout<<res.f + L * k<<"\n";
}
