#include<iostream>
using namespace std;

int main() {
	int n, x;	cin >> n>>x;
	int a=0, b=0,c=0, na, nb, nc, ans=0;
	for(int i=1; i<=n; i++) {
		int now;cin>>now;
		na = max(a+now, 0);
		nb = max(max(a+now*x, b+now*x), 0);
		nc = max(max(c+now, b+now), 0);
		a= na,b= nb,c=nc;
		ans=max(max(ans,a), max(b,c));
	}
	cout <<ans;
}