Buggy python submission (verdict: Runtime Error):
n, m = map(int, input().split())
a = [int(input()) for i in range(m)]
interval_max = 0
for i in range(len(a)-1):
    if a[i+1] - a[i] == 1:
        print(0)
        exit()
    interval_max = max(interval_max, a[i+1] - a[i])
a.insert(0, 0)
a.append(n)
for i in range(len(a)-1):
    interval_max = max(interval_max, a[i+1] - a[i])

step = [0]*(interval_max+1)
step[0] = step[1] = step[2] = 1
for i in range(3,interval_max+1):
    step[i] = (step[i-2] + step[i-1]) % 1000000007
sum_step = 1
# print(a)
for i in range(len(a)-1):
    if i == 0 or i == len(a)-2:
        sum_step *= step[a[i+1] - a[i]]
        # print(step[a[i+1] - a[i]])
    else:
        sum_step *= step[a[i+1] - a[i] - 1]
        # print(step[a[i+1] - a[i]] - 1)
    sum_step = sum_step % 1000000007
print(sum_step)
# print(step)

Fixed submission:
n, m = map(int, input().split())
if m > 0:
    a = [int(input()) for i in range(m)]
    interval_max = 0
    for i in range(len(a)-1):
        if a[i+1] - a[i] == 1:
            print(0)
            exit()
        interval_max = max(interval_max, a[i+1] - a[i])
else:
    a = []
    interval_max = n
a.insert(0, 0)
a.append(n)
for i in range(len(a)-1):
    interval_max = max(interval_max, a[i+1] - a[i])

fibb = [0]*(max(interval_max+2, 3))
fibb[0] = fibb[1] = fibb[2] = 1
for i in range(3,interval_max+2):
    fibb[i] = (fibb[i-2] + fibb[i-1]) % 1000000007
sum_step = 1
# print(a)
if m == 0:
    sum_step = fibb[n+1]
else:
    for i in range(len(a)-1):
        if i == 0 or i == len(a)-2:
            sum_step *= fibb[a[i+1] - a[i]]
            # print(fibb[a[i+1] - a[i]])
        else:
            sum_step *= fibb[a[i+1] - a[i] - 1]
            # print(fibb[a[i+1] - a[i]] - 1)
        sum_step = sum_step % 1000000007
print(sum_step)
# print(step)

Buggy python submission (verdict: Runtime Error):
n, m = map(int, input().split())
a = [int(input()) for i in range(m)]
interval_max = 0
for i in range(len(a)-1):
    if a[i+1] - a[i] == 1:
        print(0)
        exit()
    interval_max = max(interval_max, a[i+1] - a[i])
a.insert(0, 0)
a.append(n)
for i in range(len(a)-1):
    interval_max = max(interval_max, a[i+1] - a[i])

step = [0]*interval_max
step[0] = step[1] = 1
for i in range(2,interval_max):
    step[i] = (step[i-2] + step[i-1])
sum_step = 1
for i in range(len(a)-1):
    sum_step *= step[a[i+1] - a[i] - 1]
sum_step = sum_step % 1000000007
print(sum_step)

Fixed submission:
n, m = map(int, input().split())
if m > 0:
    a = [int(input()) for i in range(m)]
    interval_max = 0
    for i in range(len(a)-1):
        if a[i+1] - a[i] == 1:
            print(0)
            exit()
        interval_max = max(interval_max, a[i+1] - a[i])
else:
    a = []
    interval_max = n
a.insert(0, 0)
a.append(n)
for i in range(len(a)-1):
    interval_max = max(interval_max, a[i+1] - a[i])

fibb = [0]*(max(interval_max+2, 3))
fibb[0] = fibb[1] = fibb[2] = 1
for i in range(3,interval_max+2):
    fibb[i] = (fibb[i-2] + fibb[i-1]) % 1000000007
sum_step = 1
# print(a)
if m == 0:
    sum_step = fibb[n+1]
else:
    for i in range(len(a)-1):
        if i == 0 or i == len(a)-2:
            sum_step *= fibb[a[i+1] - a[i]]
            # print(fibb[a[i+1] - a[i]])
        else:
            sum_step *= fibb[a[i+1] - a[i] - 1]
            # print(fibb[a[i+1] - a[i]] - 1)
        sum_step = sum_step % 1000000007
print(sum_step)
# print(step)

Buggy python submission (verdict: Runtime Error):
n, m = map(int, input().split())
a = [int(input()) for i in range(m)]
interval_max = 0
for i in range(len(a)-1):
    if a[i+1] - a[i] == 1:
        print(0)
        exit()
    interval_max = max(interval_max, a[i+1] - a[i])
a.insert(0, 0)
a.append(n)
for i in range(len(a)-1):
    interval_max = max(interval_max, a[i+1] - a[i])

step = [0]*interval_max
step[0] = step[1] = 1
for i in range(2,interval_max):
    step[i] = (step[i-2] + step[i-1])
print(a, interval_max)
sum_step = 1
for i in range(len(a)-1):
    sum_step *= step[a[i+1] - a[i] - 1]
sum_step = sum_step % 1000000007
print(sum_step)

Fixed submission:
n, m = map(int, input().split())
if m > 0:
    a = [int(input()) for i in range(m)]
    interval_max = 0
    for i in range(len(a)-1):
        if a[i+1] - a[i] == 1:
            print(0)
            exit()
        interval_max = max(interval_max, a[i+1] - a[i])
else:
    a = []
    interval_max = n
a.insert(0, 0)
a.append(n)
for i in range(len(a)-1):
    interval_max = max(interval_max, a[i+1] - a[i])

fibb = [0]*(max(interval_max+2, 3))
fibb[0] = fibb[1] = fibb[2] = 1
for i in range(3,interval_max+2):
    fibb[i] = (fibb[i-2] + fibb[i-1]) % 1000000007
sum_step = 1
# print(a)
if m == 0:
    sum_step = fibb[n+1]
else:
    for i in range(len(a)-1):
        if i == 0 or i == len(a)-2:
            sum_step *= fibb[a[i+1] - a[i]]
            # print(fibb[a[i+1] - a[i]])
        else:
            sum_step *= fibb[a[i+1] - a[i] - 1]
            # print(fibb[a[i+1] - a[i]] - 1)
        sum_step = sum_step % 1000000007
print(sum_step)
# print(step)