include<bits/stdc++.h>

using namespace std;

define int long long

const int N=1e6+6; int n,a[N],x; main() { //freopen("SUBSETMIN.inp","r",stdin); //freopen("SUBSETMIN.out","w",stdout); cin>>n>>x; int t1=-1e18,t2=-1e18,t3=-1e18,ma=0; for(int i=1; i<=n; i++) cin>>a[i]; for(int i=1; i<=n; i++) { int y=max(a[i], a[i]+t1 ); int b=max({a[i]x, t1+a[i]x, t2+a[i]*x }); int c=max(t2+a[i], t3+a[i] ); t1=y; t2=b; t3=c; ma=max({ma,t2,t3}); } cout<<ma; }