#include <bits/stdc++.h>
using namespace std;
struct Node
{
	int num, step;
};
queue<Node> q;
bool vis[205];
int k[205], n, a, b;
int bfs(int x)
{
	Node node;
	node.num = x;
	node.step = 0;
	q.push(node);
	while (!q.empty())
	{
		node = q.front();
		q.pop();
		if (node.num == b)
			return node.step;
		Node tmpnode;
		tmpnode.num = node.num + k[node.num];
		if (tmpnode.num >= 1 && tmpnode.num <= n)
		{
			vis[tmpnode.num] = true;
			tmpnode.step = node.step + 1;
			q.push(tmpnode);
		}
		tmpnode.num = node.num - k[node.num];
		if (tmpnode.num >= 1 && tmpnode.num <= n)
		{
			vis[tmpnode.num] = true;
			tmpnode.step = node.step + 1;
			q.push(tmpnode);
		}
	}
}
int main()
{
	cin >> n >> a >> b;
	for (int i = 1; i <= n; i++)
		cin >> k[i];
	cout << bfs(a) << endl;
	return 0;
}