#include <bits/stdc++.h>
#include "railroad.h"
using namespace std;
typedef long long ll;
typedef pair<int,int> ii;
vector<ii> segs;
int n;
ll m[16][1<<16];
ll dp(int seg, int bm) {
if (m[seg][bm]+1) return m[seg][bm];
if (bm==(1<<n)-1) return m[seg][bm]=0;
ll l = 1ll<<62;
for (int i=0;i<n;i++) {
if (((1<<i)&~bm)) l=min(l,(seg!=-1&&segs[seg].second>segs[i].first?segs[seg].second-segs[i].first:0)+dp(i,bm|(1<<i)));
}
//printf("%d %d %d %lld\n",segs[seg].second,seg,bm,l);
return m[seg][bm]=l;
}
ll plan_roller_coaster(std::vector<int> s, std::vector<int> t) {
fill(&m[0][0],&m[n][0],-1);
n = (int) s.size();
for (int i=0;i<n;i++) segs.push_back(make_pair(s[i],t[i]));
return dp(-1,0);
}
