Buggy python submission (verdict: Runtime Error):
import sys
sys.setrecursionlimit(100000)
INF = 1000000007
n,m= map(int,input().split())
a = [0]*m
for i in range(m):
    a[i] = int(input())

step = [0]*100000
step[0] =1
step[1] =1
step[2] =2
for i in range(3,100000):
    step[i] = step[i-1] + step[i-2]

l = [a[0]-1]
for i in range(1,m):
    l.append(a[i]-a[i-1]-2)
l.append(n-a[m-1]-1)

ans = 1

for i in range(m+1):
    if step[l[i]] < 0:
        ans = 0
        break
    ans = ans*step[l[i]]
    if ans >= INF:
        ans = ans % INF

print(ans)
    

Fixed submission:
import sys
sys.setrecursionlimit(100000)
INF = 1000000007
n,m= map(int,input().split())
a = [0]*m
for i in range(m):
    a[i] = int(input())

step = [0]*(n+10)
step[0] =1
step[1] =1
step[2] =2
for i in range(3,n+10):
    step[i] = step[i-1] + step[i-2]
if m != 0:
    l = [a[0]-1]
    for i in range(1,m):
        l.append(a[i]-a[i-1]-2)
    l.append(n-a[m-1]-1)

    ans = 1

    for i in range(m+1):
        if l[i] < 0:
            ans = 0
            break
        ans = ans*step[l[i]]
        if ans >= INF:
            ans = ans % INF
if m == 0:
    ans = step[n] % INF
print(ans)

Buggy python submission (verdict: Runtime Error):
import sys
sys.setrecursionlimit(10000)
INF = 1000000007
n,m= map(int,input().split())
a = [0]*m
for i in range(m):
    a[i] = int(input())

def step(x):
    if x < 0:
        return 0
    if x == 0:
        return 1
    if x == 1:
        return 1
    if x == 2:
        return 2
    if x >= 3:
        return step(x-1)+step(x-2)

l = [a[0]-1]
for i in range(1,m):
    l.append(a[i]-a[i-1]-2)
l.append(n-a[m-1]-1)

ans = 1

for i in range(m+1):
    ans = ans*step(l[i])
    if ans >= INF:
        ans = ans % INF

print(ans)

Fixed submission:
import sys
sys.setrecursionlimit(100000)
INF = 1000000007
n,m= map(int,input().split())
a = [0]*m
for i in range(m):
    a[i] = int(input())

step = [0]*(n+10)
step[0] =1
step[1] =1
step[2] =2
for i in range(3,n+10):
    step[i] = step[i-1] + step[i-2]
if m != 0:
    l = [a[0]-1]
    for i in range(1,m):
        l.append(a[i]-a[i-1]-2)
    l.append(n-a[m-1]-1)

    ans = 1

    for i in range(m+1):
        if l[i] < 0:
            ans = 0
            break
        ans = ans*step[l[i]]
        if ans >= INF:
            ans = ans % INF
if m == 0:
    ans = step[n] % INF
print(ans)

Buggy python submission (verdict: Runtime Error):
INF = 1000000007
n,m= map(int,input().split())
a = [0]*m
for i in range(m):
    a[i] = int(input())

def step(x):
    if x < 0:
        return 0
    if x == 0:
        return 1
    if x == 1:
        return 1
    if x == 2:
        return 2
    if x >= 3:
        return step(x-1)+step(x-2)

l = [a[0]-1]
for i in range(1,m):
    l.append(a[i]-a[i-1]-2)
l.append(n-a[m-1]-1)

ans = 1

for i in range(m+1):
    ans = (ans*step(l[i]))%INF
print(ans)

Fixed submission:
import sys
sys.setrecursionlimit(100000)
INF = 1000000007
n,m= map(int,input().split())
a = [0]*m
for i in range(m):
    a[i] = int(input())

step = [0]*(n+10)
step[0] =1
step[1] =1
step[2] =2
for i in range(3,n+10):
    step[i] = step[i-1] + step[i-2]
if m != 0:
    l = [a[0]-1]
    for i in range(1,m):
        l.append(a[i]-a[i-1]-2)
    l.append(n-a[m-1]-1)

    ans = 1

    for i in range(m+1):
        if l[i] < 0:
            ans = 0
            break
        ans = ans*step[l[i]]
        if ans >= INF:
            ans = ans % INF
if m == 0:
    ans = step[n] % INF
print(ans)