Buggy python submission (verdict: Time Limit Exceeded):
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[-1 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]
now = [0,0]
queue = deque([[0,0]])
b[0][0] = 1
while queue:
    now = queue.popleft()
    if now == [n-1,m-1]:
        print(n * m - (b[n-1][m-1] + count))
        exit()
    a[now[0]][now[1]] = "#"
    for i in range(4):
        if 0 <= now[0] + y[i] < n and 0 <= now[1] + x[i] < m:
            if a[now[0]+y[i]][now[1]+x[i]] == '.':
                queue.append([now[0]+y[i],now[1]+x[i]])
                b[now[0]+y[i]][now[1]+x[i]] = b[now[0]][now[1]] + 1

print(-1)



Fixed submission:
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[-1 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]
queue = deque([[0,0]])
b[0][0] = 1
while queue:
    now = queue.popleft()
    if now == [n-1,m-1]:
        print(n * m - (b[n-1][m-1] + count))
        exit()
    a[now[0]][now[1]] = "#"
    for i in range(4):
        if 0 <= now[0] + y[i] < n and 0 <= now[1] + x[i] < m and b[now[0]+y[i]][now[1]+x[i]] == -1:
            if a[now[0]+y[i]][now[1]+x[i]] == '.':
                queue.append([now[0]+y[i],now[1]+x[i]])
                b[now[0]+y[i]][now[1]+x[i]] = b[now[0]][now[1]] + 1

print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[100000 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]

queue = deque([[0,0]])
b[0][0] = 1
while queue:
    now = queue.popleft()
    a[now[0]][now[1]] = "#"
    for i in range(4):
        if 0 <= now[0] + y[i] < n and 0 <= now[1] + x[i] < m:
            if a[now[0]+y[i]][now[1]+x[i]] == '.':
                queue.append([now[0]+y[i],now[1]+x[i]])
                b[now[0]+y[i]][now[1]+x[i]] = b[now[0]][now[1]] + 1


if b[n-1][m-1] == 100000:
    print(-1)
    exit()

ans = n * m - (b[n-1][m-1] + count)
print(ans)



Fixed submission:
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[-1 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]
queue = deque([[0,0]])
b[0][0] = 1
while queue:
    now = queue.popleft()
    if now == [n-1,m-1]:
        print(n * m - (b[n-1][m-1] + count))
        exit()
    a[now[0]][now[1]] = "#"
    for i in range(4):
        if 0 <= now[0] + y[i] < n and 0 <= now[1] + x[i] < m and b[now[0]+y[i]][now[1]+x[i]] == -1:
            if a[now[0]+y[i]][now[1]+x[i]] == '.':
                queue.append([now[0]+y[i],now[1]+x[i]])
                b[now[0]+y[i]][now[1]+x[i]] = b[now[0]][now[1]] + 1

print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[100000 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]

queue = deque([[0,0]])
b[0][0] = 1
while queue:
    now = queue.popleft()
    a[now[0]][now[1]] = "#"
    for i in range(4):
        if 0 <= now[0] + y[i] < n and 0 <= now[1] + x[i] < m:
            if a[now[0]+y[i]][now[1]+x[i]] == '.':
                queue.append([now[0]+y[i],now[1]+x[i]])
                b[now[0]+y[i]][now[1]+x[i]] = min(b[now[0]][now[1]] + 1, b[now[0]+y[i]][now[1]+x[i]])


if b[n-1][m-1] == 100000:
    print(-1)
    exit()

ans = n * m - (b[n-1][m-1] + count)
print(ans)



Fixed submission:
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[-1 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]
queue = deque([[0,0]])
b[0][0] = 1
while queue:
    now = queue.popleft()
    if now == [n-1,m-1]:
        print(n * m - (b[n-1][m-1] + count))
        exit()
    a[now[0]][now[1]] = "#"
    for i in range(4):
        if 0 <= now[0] + y[i] < n and 0 <= now[1] + x[i] < m and b[now[0]+y[i]][now[1]+x[i]] == -1:
            if a[now[0]+y[i]][now[1]+x[i]] == '.':
                queue.append([now[0]+y[i],now[1]+x[i]])
                b[now[0]+y[i]][now[1]+x[i]] = b[now[0]][now[1]] + 1

print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[100000 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]

queue = deque([[0,0]])
b[0][0] = 1
while queue:
    now = queue.popleft()

    for i in range(4):
        if 0 <= now[0] + y[i] < n and 0 <= now[1] + x[i] < m:
            if a[now[0]+y[i]][now[1]+x[i]] == '.':
                queue.append([now[0]+y[i],now[1]+x[i]])
                b[now[0]+y[i]][now[1]+x[i]] = min(b[now[0]][now[1]] + 1, b[now[0]+y[i]][now[1]+x[i]])
    a[now[0]][now[1]] = "#"

if b[n-1][m-1] == 100000:
    print(-1)
    exit()

ans = n * m - (b[n-1][m-1] + count)
print(ans)



Fixed submission:
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[-1 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]
queue = deque([[0,0]])
b[0][0] = 1
while queue:
    now = queue.popleft()
    if now == [n-1,m-1]:
        print(n * m - (b[n-1][m-1] + count))
        exit()
    a[now[0]][now[1]] = "#"
    for i in range(4):
        if 0 <= now[0] + y[i] < n and 0 <= now[1] + x[i] < m and b[now[0]+y[i]][now[1]+x[i]] == -1:
            if a[now[0]+y[i]][now[1]+x[i]] == '.':
                queue.append([now[0]+y[i],now[1]+x[i]])
                b[now[0]+y[i]][now[1]+x[i]] = b[now[0]][now[1]] + 1

print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[100000 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]

queue = deque([[0,0]])
b[0][0] = 1
while queue:
    now = queue.popleft()

    for i in range(4):
        if now[0] + y[i] < 0 or now[0] + y[i] >= n or now[1] + x[i] < 0 or now[1] + x[i] >= m:
            continue
        if a[now[0]+y[i]][now[1]+x[i]] == '.':
            queue.append([now[0]+y[i],now[1]+x[i]])
            b[now[0]+y[i]][now[1]+x[i]] = min(b[now[0]][now[1]] + 1, b[now[0]+y[i]][now[1]+x[i]])
    a[now[0]][now[1]] = "#"

if b[n-1][m-1] == 100000:
    print(-1)
    exit()

ans = n * m - (b[n-1][m-1] + count)
print(ans)



Fixed submission:
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[-1 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]
queue = deque([[0,0]])
b[0][0] = 1
while queue:
    now = queue.popleft()
    if now == [n-1,m-1]:
        print(n * m - (b[n-1][m-1] + count))
        exit()
    a[now[0]][now[1]] = "#"
    for i in range(4):
        if 0 <= now[0] + y[i] < n and 0 <= now[1] + x[i] < m and b[now[0]+y[i]][now[1]+x[i]] == -1:
            if a[now[0]+y[i]][now[1]+x[i]] == '.':
                queue.append([now[0]+y[i],now[1]+x[i]])
                b[now[0]+y[i]][now[1]+x[i]] = b[now[0]][now[1]] + 1

print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[100000 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]

queue = deque([])
now = [0,0]
b[0][0] = 1
while now != [n-1, m-1]:
    for i in range(4):
        if now[0] + y[i] < 0 or now[0] + y[i] >= n or now[1] + x[i] < 0 or now[1] + x[i] >= m:
            continue
        if a[now[0]+y[i]][now[1]+x[i]] == '.':
            queue.append([now[0]+y[i],now[1]+x[i]])
            b[now[0]+y[i]][now[1]+x[i]] = min(b[now[0]][now[1]] + 1, b[now[0]+y[i]][now[1]+x[i]])
    a[now[0]][now[1]] = "#"
    
    if queue == deque([]):
        print(-1)
        exit()
    now = queue.popleft()


ans = n * m - (b[n-1][m-1] + count)
print(ans)



Fixed submission:
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[-1 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]
queue = deque([[0,0]])
b[0][0] = 1
while queue:
    now = queue.popleft()
    if now == [n-1,m-1]:
        print(n * m - (b[n-1][m-1] + count))
        exit()
    a[now[0]][now[1]] = "#"
    for i in range(4):
        if 0 <= now[0] + y[i] < n and 0 <= now[1] + x[i] < m and b[now[0]+y[i]][now[1]+x[i]] == -1:
            if a[now[0]+y[i]][now[1]+x[i]] == '.':
                queue.append([now[0]+y[i],now[1]+x[i]])
                b[now[0]+y[i]][now[1]+x[i]] = b[now[0]][now[1]] + 1

print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[100000 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]

queue = deque([])
now = [0,0]
b[0][0] = 1
while now != [n-1, m-1]:
    for i in range(4):
        if now[0] + y[i] < 0 or now[0] + y[i] >= n or now[1] + x[i] < 0 or now[1] + x[i] >= m:
            continue
        if a[now[0]+y[i]][now[1]+x[i]] == '.':
            queue.append([now[0]+y[i],now[1]+x[i]])
        b[now[0]+y[i]][now[1]+x[i]] = min(b[now[0]][now[1]] + 1, b[now[0]+y[i]][now[1]+x[i]])
    a[now[0]][now[1]] = "#"
    
    if queue == deque([]):
        print(-1)
        exit()
    now = queue.popleft()


ans = n * m - (b[n-1][m-1] + count)
print(ans)



Fixed submission:
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[-1 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]
queue = deque([[0,0]])
b[0][0] = 1
while queue:
    now = queue.popleft()
    if now == [n-1,m-1]:
        print(n * m - (b[n-1][m-1] + count))
        exit()
    a[now[0]][now[1]] = "#"
    for i in range(4):
        if 0 <= now[0] + y[i] < n and 0 <= now[1] + x[i] < m and b[now[0]+y[i]][now[1]+x[i]] == -1:
            if a[now[0]+y[i]][now[1]+x[i]] == '.':
                queue.append([now[0]+y[i],now[1]+x[i]])
                b[now[0]+y[i]][now[1]+x[i]] = b[now[0]][now[1]] + 1

print(-1)

Buggy python submission (verdict: Runtime Error):
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[100000 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]

queue = deque([])
now = [0,0]
b[0][0] = 1
while now != [n-1, m-1]:
    for i in range(4):
        if now[0] + y[i] < 0 or now[0] + y[i] >= n or now[1] + x[i] < 0 or now[1] + x[i] >= m:
            continue
        if a[now[0]+y[i]][now[1]+x[i]] == '.':
            queue.append([now[0]+y[i],now[1]+x[i]])
        b[now[0]+y[i]][now[1]+x[i]] = min(b[now[0]][now[1]] + 1, b[now[0]+y[i]][now[1]+x[i]])
    a[now[0]][now[1]] = "#"
    now = queue.popleft()


ans = n * m - (b[n-1][m-1] + count)
print(ans)

Fixed submission:
n,m = map(int,input().split())
from collections import deque
a = []
for _ in range(n):
    a.append(list(input()))

count = 0
for x in a:
    count += x.count("#")
#print(count)

b = [[-1 for i in range(m)] for i in range(n)]
#print(a)

x = [0, 0, -1, 1]
y = [-1, 1, 0, 0]
queue = deque([[0,0]])
b[0][0] = 1
while queue:
    now = queue.popleft()
    if now == [n-1,m-1]:
        print(n * m - (b[n-1][m-1] + count))
        exit()
    a[now[0]][now[1]] = "#"
    for i in range(4):
        if 0 <= now[0] + y[i] < n and 0 <= now[1] + x[i] < m and b[now[0]+y[i]][now[1]+x[i]] == -1:
            if a[now[0]+y[i]][now[1]+x[i]] == '.':
                queue.append([now[0]+y[i],now[1]+x[i]])
                b[now[0]+y[i]][now[1]+x[i]] = b[now[0]][now[1]] + 1

print(-1)