#include<iostream>
#include<algorithm>
#include<cstring>
#include<vector>
#include<queue>

using namespace std;
typedef pair<int, int>PII;
const int N = 210;
int lan[N], dis[N];
int n, a, b;
bool st[N];
queue<PII>q;
bool judge(int x)
{
	if (x<1 || x>n || st[x]) return false;
	else return true;
}
int bfs()
{
	int result = -1;
	q.push({ b, 0 });
	while (!q.empty())
	{
		int num = q.front().first;
		int dist = q.front().second;
		if (num == a)
		{
			result = dist;
			break;
		}
		st[num] = true;
		q.pop();
		for (int i = 1; i <= n; i++)
		{
			if (st[i] == false)
			{
				if (i + lan[i] == num) q.push({ i, dist + 1 });
				if (i - lan[i] == num) q.push({ i, dist + 1 });
			}
		}
	}
	return result;
}
int main()
{
	memset(dis, -1, sizeof(dis));
	cin >> n >> a >> b;
	for (int i = 1; i <= n; i++)
	{
		cin >> lan[i];
	}
	int ans = bfs();
	cout << ans << endl;
	return 0;
}