#include<bits/stdc++.h>
#include<fstream>
//#pragma GCC optimize("O3")
//#pragma GCC target("avx2")
using namespace std;
#define sz(a) (int)a.size()
#define ALL(v) v.begin(), v.end()
#define ALLR(v) v.rbegin(), v.rend()
#define ll long long
#define pb push_back
#define forr(i, a, b) for(int i = a; i < b; i++)
#define dorr(i, a, b) for(int i = a; i >= b; i--)
#define ld long double
#define vt vector
#include<fstream>
#define fi first
#define se second
#define pll pair<ll, ll>
#define pii pair<int, int>
#define mpp make_pair
const ld PI = 3.14159265359, prec = 1e-9;;
//using u128 = __uint128_t;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, -1, 0, 1};
const ll mod = 1e9 + 7, pr = 31;
const int mxn = 2e5 + 5, mxd = 250 * 250, sq = 100, mxv = 5e4 + 1, mxq = 2e6 + 5, T = 1000;
//const int base = (1 <<18);
const ll inf = 2e9 + 5, neg = -69420, inf2 = 1e14;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
#include <vector>
#include <cassert>
#include <cstdio>
//#include "jumps.h"
#include <vector>
int n;
bool sub1 = 1;
int h[mxn + 1], l[mxn + 1], r[mxn + 1], dis[mxn + 1], up[mxn + 1][18], upr[mxn + 1][18];
pii mx[mxn + 1][18];
vt<int>adj[mxn + 1];
int getmx(int l, int r){
if(l > r)return(-1);
int lg = __lg(r - l + 1);
return(max(mx[l][lg], mx[r - (1 << lg) + 1][lg]).se);
}
void init(int N, std::vector<int> H) {
n = N;
for(int i = 1; i <= n; i++){
h[i] = H[i - 1]; sub1 &= (h[i] == i);
}
h[0] = inf;
vt<int>st;
for(int i = 1; i <= n; i++){
while(sz(st) && h[st.back()] <= h[i])st.pop_back();
if(sz(st))l[i] = st.back();
st.pb(i);
}
st.clear();
for(int i = n; i >= 1; i--){
while(sz(st) && h[st.back()] <= h[i])st.pop_back();
if(sz(st))r[i] = st.back();
st.pb(i); upr[i][0] = r[i];
}
for(int i = 1; i <= n; i++){
if(h[l[i]] > h[r[i]])up[i][0] = l[i];
else up[i][0] = r[i];
mx[i][0] = mpp(h[up[i][0]], i);
}
for(int i = 1; i < 18; i++){
for(int j = 1; j <= n; j++){
up[j][i] = up[up[j][i - 1]][i - 1];
upr[j][i] = upr[upr[j][i - 1]][i - 1];
}
for(int j = 1; j + (1 << i) - 1 <= n; j++){
mx[j][i] = max(mx[j][i - 1], mx[j + (1 << (i - 1))][i - 1]);
}
}
for(int i = 1; i <= n; i++){
if(l[i])adj[i].pb(l[i]);
if(r[i])adj[i].pb(r[i]);
}
}
int minimum_jumps(int A, int B, int C, int D) {
A++; B++; C++; D++;
if(sub1)return(C - B);
if(C == D){
int mx = -1, u = getmx(max(l[C] + 1, A), B);
if(u == -1)return(-1);
int ans = 0;
for(int i = 17; i >= 0; i--){
if(h[up[u][i]] <= h[C]){
ans += (1 << i); u = up[u][i];
}
}
for(int i = 17; i >= 0; i--){
if(h[upr[u][i]] <= h[C]){
ans += (1 << i); u = upr[u][i];
}
}
if(u != C)return(-1);
return(ans);
}else{
queue<int>q;
for(int i = 1; i <= n; i++)dis[i] = -1;
for(int i = A; i <= B; i++){
dis[i] = 0; q.push(i);
}
while(!q.empty()){
int nw = q.front(); q.pop();
if(nw >= C && nw <= D)return(dis[nw]);
for(auto i: adj[nw]){
if(dis[i] == -1){
dis[i] = dis[nw] + 1; q.push(i);
}
}
}
return -1;
}
}
#include <vector>
/*
int main() {
int N, Q;
assert(2 == scanf("%d %d", &N, &Q));
std::vector<int> H(N);
for (int i = 0; i < N; ++i) {
assert(1 == scanf("%d", &H[i]));
}
init(N, H);
for (int i = 0; i < Q; ++i) {
int A, B, C, D;
assert(4 == scanf("%d %d %d %d", &A, &B, &C, &D));
printf("%d\n", minimum_jumps(A, B, C, D));
}
return 0;
}
*/
