Buggy python submission (verdict: Time Limit Exceeded):
#!/usr/bin/env python3
import sys


input = sys.stdin.readline
def IS(cb): return cb(input().strip())
def IL(cb): return [cb(s) for s in input().strip().split()]
def IR(cb, rows): return [IS(cb) for _ in range(rows)]
def ILL(cb, rows): return [IL(cb) for _ in range(rows)]


def solve():
    N, K = IL(int)
    A = IL(lambda x: int(x) - 1)
    memo = [0]
    i = 0
    while(not A[i] in memo):
        memo.append(A[i])
        idx = i
        i = A[i]
    if K < len(memo):
        print(memo[K] + 1)
    else:
        loop = memo[memo.index(A[i]):]
        print(loop[(K - (len(memo) - len(loop))) % len(loop)] + 1)


solve()


Fixed submission:
#!/usr/bin/env python3
import sys


input = sys.stdin.readline
def IS(cb): return cb(input().strip())
def IL(cb): return [cb(s) for s in input().strip().split()]
def IR(cb, rows): return [IS(cb) for _ in range(rows)]
def ILL(cb, rows): return [IL(cb) for _ in range(rows)]


def solve():
    N, K = IL(int)
    A = IL(lambda x: int(x) - 1)
    memo = [0]
    visited = [False] * N
    i = 0
    while(not visited[A[i]]):
        memo.append(A[i])
        visited[A[i]] = True
        i = A[i]
    if K < len(memo):
        print(memo[K] + 1)
    else:
        loop = memo[memo.index(A[i]):]
        print(loop[(K - (len(memo) - len(loop))) % len(loop)] + 1)


solve()

Buggy python submission (verdict: Time Limit Exceeded):
#!/usr/bin/env python3
import sys


input = sys.stdin.readline
def IS(cb): return cb(input().strip())
def IL(cb): return [cb(s) for s in input().strip().split()]
def IR(cb, rows): return [IS(cb) for _ in range(rows)]
def ILL(cb, rows): return [IL(cb) for _ in range(rows)]


def solve():
    N, K = IL(int)
    A = IL(lambda x: int(x) - 1)
    memo = [0]
    i = 0
    while(not A[i] in memo):
        memo.append(A[i])
        i = A[i]
    j = 0
    if K < len(memo):
        print(memo[K] + 1)
    else:
        loop = memo[memo.index(A[i]):]
        print(loop[(K - (len(memo) - len(loop))) % len(loop)] + 1)


solve()


Fixed submission:
#!/usr/bin/env python3
import sys


input = sys.stdin.readline
def IS(cb): return cb(input().strip())
def IL(cb): return [cb(s) for s in input().strip().split()]
def IR(cb, rows): return [IS(cb) for _ in range(rows)]
def ILL(cb, rows): return [IL(cb) for _ in range(rows)]


def solve():
    N, K = IL(int)
    A = IL(lambda x: int(x) - 1)
    memo = [0]
    visited = [False] * N
    i = 0
    while(not visited[A[i]]):
        memo.append(A[i])
        visited[A[i]] = True
        i = A[i]
    if K < len(memo):
        print(memo[K] + 1)
    else:
        loop = memo[memo.index(A[i]):]
        print(loop[(K - (len(memo) - len(loop))) % len(loop)] + 1)


solve()

Buggy python submission (verdict: Runtime Error):
#!/usr/bin/env python3
import sys


input = sys.stdin.readline
def IS(cb): return cb(input().strip())
def IL(cb): return [cb(s) for s in input().strip().split()]
def IR(cb, rows): return [IS(cb) for _ in range(rows)]
def ILL(cb, rows): return [IL(cb) for _ in range(rows)]


def solve():
    N, K = IL(int)
    A = IL(lambda x: int(x) - 1)
    memo = []
    i = 0
    while(i < N and A[i] != 0):
        memo.append(A[i])
        i += 1
    print(memo[K % len(memo)] + 1)


solve()


Fixed submission:
#!/usr/bin/env python3
import sys


input = sys.stdin.readline
def IS(cb): return cb(input().strip())
def IL(cb): return [cb(s) for s in input().strip().split()]
def IR(cb, rows): return [IS(cb) for _ in range(rows)]
def ILL(cb, rows): return [IL(cb) for _ in range(rows)]


def solve():
    N, K = IL(int)
    A = IL(lambda x: int(x) - 1)
    memo = [0]
    visited = [False] * N
    i = 0
    while(not visited[A[i]]):
        memo.append(A[i])
        visited[A[i]] = True
        i = A[i]
    if K < len(memo):
        print(memo[K] + 1)
    else:
        loop = memo[memo.index(A[i]):]
        print(loop[(K - (len(memo) - len(loop))) % len(loop)] + 1)


solve()