Petya and Vasya are playing a game. Petya's got *n* non-transparent glasses, standing in a row. The glasses' positions are indexed with integers from 1 to *n* from left to right. Note that the positions are indexed but the glasses are not.

First Petya puts a marble under the glass in position *s*. Then he performs some (possibly zero) shuffling operations. One shuffling operation means moving the glass from the first position to position *p*<sub class="lower-index">1</sub>, the glass from the second position to position *p*<sub class="lower-index">2</sub> and so on. That is, a glass goes from position *i* to position *p*<sub class="lower-index">*i*</sub>. Consider all glasses are moving simultaneously during one shuffling operation. When the glasses are shuffled, the marble doesn't travel from one glass to another: it moves together with the glass it was initially been put in.

After all shuffling operations Petya shows Vasya that the ball has moved to position *t*. Vasya's task is to say what minimum number of shuffling operations Petya has performed or determine that Petya has made a mistake and the marble could not have got from position *s* to position *t*.
The first line contains three integers: *n*, *s*, *t* (1 ≤ *n* ≤ 10<sup class="upper-index">5</sup>; 1 ≤ *s*, *t* ≤ *n*) — the number of glasses, the ball's initial and final position. The second line contains *n* space-separated integers: *p*<sub class="lower-index">1</sub>, *p*<sub class="lower-index">2</sub>, ..., *p*<sub class="lower-index">*n*</sub> (1 ≤ *p*<sub class="lower-index">*i*</sub> ≤ *n*) — the shuffling operation parameters. It is guaranteed that all *p*<sub class="lower-index">*i*</sub>'s are distinct.

Note that *s* can equal *t*.
from collections import Counter
import string
import math
import sys
def array_int():
    return [int(i) for i in sys.stdin.readline().split()]
def vary(arrber_of_variables):
    if arrber_of_variables==1:
        return int(sys.stdin.readline())
    if arrber_of_variables>=2:
        return map(int,sys.stdin.readline().split()) 
def makedict(var):
    return dict(Counter(var))
mod=1000000007
#i am noob wanted to be better and trying hard for that
n,s,t=vary(3)
num=array_int()
count=0
while 1:
    if count>n*n:
        print(-1)
        break
    if s==t:
        print(count)
        break
    s=num[s-1]
    count+=1
    



        







    


            
        


        

   





    
        






    


            


        

        
        




    











            
        


        






                 

            
    

















        






        


        



