A133

#include <bits/stdc++.h>
using namespace std;
int vis[1005]={},n,k,x,a[205]={},z;
queue<int>q;
int main(){
    memset(vis,-1,sizeof(vis));
    cin>>z>>n>>k;
    for(int i=1;i<=z;i++){
        cin>>a[i];
    }
    vis[n]=0;
    q.push(n);
    while(q.size()){
        x=q.front();
        q.pop();
        if(x==k){
            cout<<vis[x];
            return 0;
        }     
        if(vis[x-a[x]]==-1&&x-a[x]>=1){
            vis[x-a[x]]=vis[x]+1;
            q.push(x-a[x]);
        }
        if(vis[x+a[x]]==-1&&x+a[x]<=z){
            vis[x+a[x]]=vis[x]+1;
            q.push(x+a[x]);
        }       
    }
    cout<<-1;
    return 0;
}