#include "lawn.h"
#include <iostream>
using namespace std;
using ll=long long;
namespace
{
const int MN=5013;
const ll inf64=1e18;
int N; ll C, B;
ll A[MN], V[MN];
ll f[MN][MN], dp[MN];
void init(int L)
{
ll ans=0;
int cur=0;
for (int i=L; i<=N; i++)
{
if (cur+V[i]>C)
{
ans+=A[i]+B;
ll cnt=(V[i]-C+cur)/C;
if ((V[i]-C+cur)%C)
{
ans+=(cnt+1)*A[i]+cnt*B;
cur=(V[i]-C+cur)%C;
}
else
{
ans+=cnt*A[i]+cnt*B;
cur=0;
}
}
else
{
ans+=A[i];
cur+=V[i];
}
f[L][i]=ans;
if (cur) f[L][i]+=B;
}
}
}
ll mow(int n, int c, int b, vector<int> &a, vector<int> &v)
{
N=n; C=c; B=b;
for (int i=1; i<=N; i++) A[i]=a[i-1];
for (int i=1; i<=N; i++) V[i]=v[i-1];
for (int i=1; i<=N; i++) init(i);
dp[0]=0;
for (int i=1; i<=N; i++)
{
dp[i]=inf64;
for (int j=0; j<i; j++)
{
dp[i]=min(dp[i], dp[j]+f[j+1][i]);
}
//cerr<<i<<": "<<dp[i]<<endl;
}
return dp[N];
}
