#include <bits/stdc++.h>
//#include "jumps.h"
using namespace std;
const int maxN = 2e5 + 5;
int n;
vector<int> H;
int L[20][maxN], R[20][maxN], jump[20][maxN];
void init(int N, vector<int> h) {
n = N; H = h;
H.insert(H.begin(), 1e9 + 1);
H.insert(H.end(), 1e9 + 1);
stack<int> st; st.push(0);
for (int i = 1; i <= n; i++) {
while (H[i] > H[st.top()]) st.pop();
L[0][i] = st.top();
st.push(i);
}
while (st.size()) st.pop();
st.push(n + 1);
for (int i = n; i >= 1; i--) {
while (H[i] > H[st.top()]) st.pop();
R[0][i] = st.top();
st.push(i);
}
L[0][0] = L[0][n + 1] = 0;
R[0][0] = R[0][n + 1] = n + 1;
for (int i = 0; i <= n + 1; i++)
if (H[L[0][i]] > H[R[0][i]]) jump[0][i] = L[0][i];
else jump[0][i] = R[0][i];
//for (int i = 1; i <= n; i++)
//cout << L[0][i] << ' ' << R[0][i] << ' ' << jump[0][i] << '\n';
for (int k = 1; k <= 17; k++)
for (int i = 1; i <= n; i++) {
L[k][i] = L[k - 1][L[k - 1][i]];
R[k][i] = R[k - 1][R[k - 1][i]];
jump[k][i] = jump[k - 1][jump[k - 1][i]];
}
}
int minimum_jumps(int A, int B, int C, int D) {
A++; B++; C++; D++;
if (H[B] > H[C]) return -1;
int pos = B;
for (int k = 17; k >= 0; k--) {
if (A <= L[k][pos] && H[L[k][pos]] < H[C])
pos = L[k][pos];
}
B = pos;
int res = 0;
for (int k = 17; k >= 0; k--) {
if (H[jump[k][B]] <= H[C]) {
res += (1 << k);
B = jump[k][B];
}
}
if (B == C) return res;
if (H[R[0][B]] > H[C]) {
for (int k = 17; k >= 0; k--)
if (H[L[k][B]] <= H[C]) {
res += (1 << k);
B = L[k][B];
}
}
else {
for (int k = 17; k >= 0; k--)
if (H[R[k][B]] <= H[C]) {
res += (1 << k);
B = R[k][B];
}
}
if (B == C) return res;
return -1;
}
/*
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;
}*/
/*
7 3
3 2 1 6 4 5 7
4 4 6 6
1 3 5 6
0 1 2 2
*/
