Buggy python submission (verdict: Runtime Error):
def calc(i):
    ans_list = [i]
    ans_set = set([i])
    count = 1
    i = a[i]
    while (i not in ans_set) & (count <= k):
        ans_list.append(i)
        ans_set.add(i)
        count += 1
        i = a[i]
    index = ans_list.index(i)
    ans_list.append(i)
    return count, ans_list

n, k = map(int, input().split())
a = [int(i) - 1 for i in input().split()]

count, ans_list = calc(0)
if count <= n:
    index = ans_list.index(ans_list[-1])
    k = k - index
    ans_list = ans_list[index + 1:]
    print(ans_list[k % len(ans_list) - 1] + 1)
else:
    print(ans_list[-1] + 1)

Fixed submission:
n, k = map(int, input().split())
a = [int(i) - 1 for i in input().split()]
visit = {0}
tmp = 0
a_list = [0]
ans = True
for i in range(k):
    tmp = a[tmp]
    if tmp in visit:
        left = a_list.index(tmp)
        ans = False
        print(a_list[left + (k - left) % (i + 1 - left)] + 1)
        break
    else:
        visit.add(tmp)
        a_list.append(tmp)
if ans:
    print(tmp + 1)

Buggy python submission (verdict: Runtime Error):
def calc(i, k):
    ans_list = [i]
    ans_set = set([i])
    count = 1
    i = a[i]
    while (i not in ans_set) & (count < k):
        ans_list.append(i)
        ans_set.add(i)
        count += 1
        i = a[i]
    index = ans_list.index(i)
    ans_list.append(i)
    return count, ans_list

n, k = map(int, input().split())
a = [int(i) - 1 for i in input().split()]

count, ans_list = calc(0, k)
if count < k:
    index = ans_list.index(ans_list[-1])
    k = k - index
    ans_list = ans_list[index + 1:]
    print(ans_list[k % len(ans_list) - 1] + 1)
else:
    print(ans_list[-1] + 1)

Fixed submission:
n, k = map(int, input().split())
a = [int(i) - 1 for i in input().split()]
visit = {0}
tmp = 0
a_list = [0]
ans = True
for i in range(k):
    tmp = a[tmp]
    if tmp in visit:
        left = a_list.index(tmp)
        ans = False
        print(a_list[left + (k - left) % (i + 1 - left)] + 1)
        break
    else:
        visit.add(tmp)
        a_list.append(tmp)
if ans:
    print(tmp + 1)

Buggy python submission (verdict: Runtime Error):
def calc(i, k):
    ans_list = [i]
    ans_set = set([i])
    count = 1
    i = a[i]
    while (i not in ans_set) & (count < k):
        ans_list.append(i)
        ans_set.add(i)
        count += 1
        i = a[i]
    index = ans_list.index(i)
    ans_list.append(i)
    return count, ans_list

n, k = map(int, input().split())
a = [int(i) - 1 for i in input().split()]

count, ans_list = calc(0, k)
if count < k:
    index = ans_list.index(ans_list[-1])
    k = k - index
    ans_list = ans_list[index + 1:]
    print(ans_list[k % len(ans_list) - 1] + 1)
else:
    print(ans_list[k] + 1)

Fixed submission:
n, k = map(int, input().split())
a = [int(i) - 1 for i in input().split()]
visit = {0}
tmp = 0
a_list = [0]
ans = True
for i in range(k):
    tmp = a[tmp]
    if tmp in visit:
        left = a_list.index(tmp)
        ans = False
        print(a_list[left + (k - left) % (i + 1 - left)] + 1)
        break
    else:
        visit.add(tmp)
        a_list.append(tmp)
if ans:
    print(tmp + 1)

Buggy python submission (verdict: Time Limit Exceeded):
def calc(i, k):
    ans_list = [i]
    count = 1
    i = a[i]
    while (i not in ans_list) & (count < n):
        ans_list.append(i)
        count += 1
        i = a[i]
    index = ans_list.index(i)
    ans_list.append(i)
    return count, ans_list

n, k = map(int, input().split())
a = [int(i) - 1 for i in input().split()]

count, ans_list = calc(0, k)
if count < k:
    index = ans_list.index(ans_list[-1])
    k = k - index
    ans_list = ans_list[index + 1:]
    print(ans_list[k % len(ans_list) - 1] + 1)
else:
    print(ans_list[k] + 1)

Fixed submission:
n, k = map(int, input().split())
a = [int(i) - 1 for i in input().split()]
visit = {0}
tmp = 0
a_list = [0]
ans = True
for i in range(k):
    tmp = a[tmp]
    if tmp in visit:
        left = a_list.index(tmp)
        ans = False
        print(a_list[left + (k - left) % (i + 1 - left)] + 1)
        break
    else:
        visit.add(tmp)
        a_list.append(tmp)
if ans:
    print(tmp + 1)

Buggy python submission (verdict: Runtime Error):
def calc(i, k):
    ans_list = [i]
    count = 1
    i = a[i]
    while (i not in ans_list) & (count < k):
        ans_list.append(i)
        count += 1
        i = a[i]
    index = ans_list.index(i)
    ans_list.append(i)
    return count, ans_list

n, k = map(int, input().split())
a = [int(i) - 1 for i in input().split()]

count, ans_list = calc(0, k)
if count < k:
    index = ans_list.index(ans_list[-1])
    k = k - index
    ans_list = ans_list[index + 1:]
    print(ans_list[k % len(ans_list) - 1] + 1)
else:
    print(ans_list[k] + 1)

Fixed submission:
n, k = map(int, input().split())
a = [int(i) - 1 for i in input().split()]
visit = {0}
tmp = 0
a_list = [0]
ans = True
for i in range(k):
    tmp = a[tmp]
    if tmp in visit:
        left = a_list.index(tmp)
        ans = False
        print(a_list[left + (k - left) % (i + 1 - left)] + 1)
        break
    else:
        visit.add(tmp)
        a_list.append(tmp)
if ans:
    print(tmp + 1)