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*.
a = input()
b = input()
a_1 = ""
lst =[]
for i in range(len(a)):
    if a[i] != " ":
        a_1 = a_1 + a[i]
    else:
        lst.append(int(a_1))
        a_1 = ""
lst.append(int(a_1))
n = lst[0]
s = lst[1]
t = lst[2]
a_1 = ""
lst2 = []
for i in range(len(b)):
    if b[i] != " ":
        a_1 = a_1 + b[i]
    else:
        lst2.append(int(a_1))
        a_1 = ""
lst2.append(int(a_1))
key = -1
if  s == t:
    key = 0
else:
    conter = 0
    for i in range(n):
        conter = conter + 1
        if lst2[s - 1] == t:
            key = conter
            break
        s = lst2[s - 1]
print(key)

