#include<bits/stdc++.h>
using namespace std;
int main()
{   
    //bfs
    int n,st,en,a[205],d[205][3],bz[205],c[2]={-1,1};
    scanf("%d%d%d",&n,&st,&en);
    if(st == en)
    {
        printf("%d",0);
        return 0;
    }

    memset(d,0,sizeof(d));
    memset(bz,0,sizeof(bz));

    for(int i=1;i<=n;i++) scanf("%d",&a[i]);

    d[1][1] = st; //楼层
    d[1][2] = 0; //到达这一层要的步数
    bz[st] = 1;

    int i=0,j=1;
    while(i<j)
    {
        i++;
        for(int t = 0;t<=1;t++)
        {
            int k = d[i][1]+a[d[i][1]]*c[t];
            if(k>=1 && k<=n)
            {
                j++;
                d[j][1] = k;
                d[j][2] = d[i][2]+1;
                if(bz[k] == 0)
                {
                    bz[k] =1;
                    if(k == en)
                    {
                        printf("%d",d[j][2]);
                        return 0;
                    }
                }
                else j--; 
            }
        }
    }
    printf("%d",-1);
    return 0;
}