#include<bits/stdc++.h>
#include "railroad.h"
#define ll long long
#define fi first
#define se second
#define pb push_back
using namespace std;
int n;const int M=100000;
int S[20],T[20];
ll dp[M][21];
ll go(int x,int y)
{
if(x>n-1)return 0;
ll z=0;
if(T[x]<=S[y])return 0;
z=T[x]-S[y];return z;
}
ll d(int x,int mask,int last)
{
if(x==n)return 0;
ll &u=dp[mask][last];
if(u!=-1)return u;
u=1e17;ll one=1;
for(int i=0;i<n;i++)
{
ll w=(one<<i);
if((mask&w)>0)continue;
ll z=go(last,i);
u=min(u,d(x+1,mask+w,i)+z);
}
return u;
}
long long plan_roller_coaster(vector<int> s,vector<int> t) {
memset(dp,-1,sizeof dp);
n = (int) s.size();
for(int i=0;i<n;i++)
{
S[i]=s[i];
T[i]=t[i];
}
ll x=d(0,0,n+2);
return x;
}
