#include "railroad.h"
#include <bits/stdc++.h>
#define Loop(x,l,r) for (ll x = (l); x < (ll)(r); ++x)
#define LoopR(x,l,r) for (ll x = (r)-1; x >= (ll)(l); --x)
typedef long long ll;
typedef std::pair<int, int> pii;
typedef std::pair<ll , ll > pll;
using namespace std;
long long plan_roller_coaster(std::vector<int> s, std::vector<int> t)
{
s.push_back(1e9+10);
t.push_back(1);
int n = s.size();
set<pii> S;
Loop (i,0,n)
S.insert({s[i], i});
ll ans = 0;
int p = 1;
while (S.size()) {
auto it = S.lower_bound(pii{p, INT_MIN});
if (it == S.end())
--it;
int i = it->second;
ans += max(0, p - s[i]);
p = t[i];
S.erase(it);
}
ans += p-1;
return ans;
}
