CLS
OPEN "input.txt" FOR INPUT AS #1
OPEN "output.txt" FOR OUTPUT AS #2
INPUT #1, n
DIM a(n)
FOR i = 0 TO n - 1
INPUT #1, a(i)
NEXT i
INPUT #1, k
FOR i = 0 TO n - 1
IF a(i) = k THEN l = i
NEXT i
a(l) = 0
m = 1
p = k
DO UNTIL k = 0
p = k
m = m + 1
k = a(k - 1)
a(p - 1) = 0
LOOP
PRINT #2, m - 1
SYSTEM