#include <bits/stdc++.h> using namespace std; #define int long long int int32_t main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n,k; cin>>n>>k; int arr[n]; int s1=0,s2=0; int f=0; for(int i=0;i<n;i++){ cin>>arr[i]; if(arr[i]>=0&&f==0) s1+=arr[i]; if(f==1) s2+=arr[i]; if(arr[i]<0) f=1; } if(k==1) cout<<max(s1,s2)<<endl; else cout<<s1+s2<<endl; return 0; }