#include <bits/stdc++.h> using namespace std; #define endl "\n" #define int long long #define pii pair<int, int> #define ff first #define ss second #define entire(x) (x).begin(), (x).end() int32_t main(){ ios::sync_with_stdio(false); cin.tie(nullptr); int n, k; cin >> n >> k; vector<int> a(n); for (int i = 0; i < n; i++) cin >> a[i]; int idx = -1; for (int i = 0; i < n; i++) if (a[i] < 0) idx = i; int sum = accumulate(entire(a), 0ll), bef = accumulate(a.begin(), a.begin() + idx, 0ll); if (k == 1){ int ans = max(sum - a[idx], max(bef, sum - bef - a[idx])); cout << ans << endl; } else cout << sum - a[idx] << endl; return 0; }