MLE on #1#2#3#4#5#6#8#10#11#12#13#14#15#16

#include <bits/stdc++.h>
#define int long long
using namespace std;
int n,a,b;
int k[207];
int lmin=1145141919810;
void dfs(int c,int s){
	if(c==b){
		if(s<lmin) lmin=s;
		return ;
	}
	if(c>0&&c<=n){
		dfs(c+k[c],s+1);
		dfs(c-k[c],s+1);
	}
}
signed main(){
	scanf("%lld%lld%lld",&n,&a,&b);
	for(int i=1;i<=n;i++){
		scanf("%lld",&k[i]);
	}
	dfs(a,0);
	if(lmin==1145141919810){
		printf("-1");
	}else{
		printf("%lld",lmin);
	}
	return 0;
}