#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
ll n;
ll sy, sx;
ll ey, ex;
cin >> n;
cin >> sy >> sx;
cin >> ey >> ex;
vector<ll> lines(n);
for (ll i = 0; i < n; i++) {
cin >> lines[i];
}
// Zero-based indices
sx--; sy--;
ex--; ey--;
// If start == end
if (sx == ex && sy == ey) {
cout << 0;
return 0;
}
auto encode = [&](ll x, ll y) {
return (y << 32) | x;
};
queue<array<ll,3>> q;
q.push({sx, sy, 0});
unordered_set<ll> visited;
visited.reserve(n * 2);
while (!q.empty()) {
auto [x, y, dist] = q.front();
q.pop();
// Move left
{
ll nx = x, ny = y;
if (x > 0) {
nx = x - 1;
} else if (x == 0 && y > 0) {
ny = y - 1;
nx = lines[ny];
} else {
nx = -1; // invalid
}
if (nx >= 0) {
ll code = encode(nx, ny);
if (visited.find(code) == visited.end()) {
if (nx == ex && ny == ey) {
cout << dist + 1;
return 0;
}
visited.insert(code);
q.push({nx, ny, dist + 1});
}
}
}
// Move right
{
ll nx = x, ny = y;
if (x < lines[y]) {
nx = x + 1;
} else if (x == lines[y] && y < n - 1) {
ny = y + 1;
nx = 0;
} else {
nx = -1; // invalid
}
if (nx >= 0) {
ll code = encode(nx, ny);
if (visited.find(code) == visited.end()) {
if (nx == ex && ny == ey) {
cout << dist + 1;
return 0;
}
visited.insert(code);
q.push({nx, ny, dist + 1});
}
}
}
// Move up
if (y > 0) {
ll ny = y - 1;
ll nx = x > lines[ny] ? lines[ny] : x;
ll code = encode(nx, ny);
if (visited.find(code) == visited.end()) {
if (nx == ex && ny == ey) {
cout << dist + 1;
return 0;
}
visited.insert(code);
q.push({nx, ny, dist + 1});
}
}
// Move down
if (y < n - 1) {
ll ny = y + 1;
ll nx = x > lines[ny] ? lines[ny] : x;
ll code = encode(nx, ny);
if (visited.find(code) == visited.end()) {
if (nx == ex && ny == ey) {
cout << dist + 1;
return 0;
}
visited.insert(code);
q.push({nx, ny, dist + 1});
}
}
}
return 0;
}
