#include/*PRESS*/<stdio.h>

            int a[1<<5
         *5],n,x,v,m;int
         main(      int c
       ,char*        *g){
       for(m
       =--c?
       3.e7:
       2020;
  scanf("%d%*c",&*&x
 )>0;a[x]=++n);for(
       a[x]=0
       ;n<m;v
       =a[x]?
       n-a[x]
       :0,a[x
       ]=n++,
       x=+v);
      printf(""
    "%d\n",v|0);}

/*** TO PAY RESPECTS ***/