#include<iostream>
#include<cstdio>
using namespace std;
int sum1[100001]={0},sum2[100001]={0},a[100001]={0};
int main()
{freopen("maxsum.in","r",stdin);freopen("maxsum.out","w",stdout);int n,i,j,maxn,minn;maxn=-2100000000;scanf("%d",&n);for (i=1;i<=n;++i){scanf("%d",&a[i]);sum1[i]=sum1[i-1]+a[i];}for (i=n;i>=1;--i)sum2[i]=sum2[i+1]+a[i];minn=2100000000;for (i=1;i<=n;++i){if (sum1[i]-minn>maxn) maxn=sum1[i]-minn;if (sum1[i]<minn) minn=sum1[i];    }minn=-2100000000;for (i=1;i<=n;++i){if (minn+sum2[i]>maxn) maxn=minn+sum2[i];if (sum1[i]>minn) minn=sum1[i];}printf("%d\n",maxn);fclose(stdin);fclose(stdout);
}

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int a[20001]={0},b[20001]={0},cc[80001]={0},sum[100000]={0},dd[100000]={0};
int main()
{freopen("milktemp.in","r",stdin);freopen("milktemp.out","w",stdout);int maxn=0,n,i,j,x,y,z,tot=0,size,ans=0;scanf("%d%d%d%d",&n,&x,&y,&z);for (i=1;i<=n;++i){scanf("%d%d",&a[i],&b[i]);++tot;cc[tot]=a[i];++tot;cc[tot]=b[i];}sort(cc+1,cc+tot+1);size=unique(cc+1,cc+tot+1)-cc-1;for (i=1;i<=n;++i){a[i]=upper_bound(cc+1,cc+size+1,a[i])-cc-1;b[i]=upper_bound(cc+1,cc+size+1,b[i])-cc-1;maxn=max(maxn,max(a[i],b[i]));}maxn+=2;for (i=1;i<=n;++i){dd[0]+=x;dd[a[i]]-=x;dd[a[i]]+=y;dd[b[i]+1]-=y;dd[b[i]+1]+=z;dd[maxn]-=z;}ans=sum[0]=dd[0];for (i=1;i<=maxn;++i){sum[i]=sum[i-1]+dd[i];ans=max(ans,sum[i]);}printf("%d\n",ans);fclose(stdin);fclose(stdout);
}