Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

inf = 10**9
dp = [[inf for j in range(w)] for k in range(h)]
dp[x1-1][y1-1] = 0
q = deque([(x1-1, y1-1)])

while q:
    x, y = q.popleft()
    if (x, y) == (x2-1, y2-1):
        break
    c = dp[x][y]
    for i in range(x+1, min(x+k+1, h)):
        if g[i][y] == "@":
            break
        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
            q.append((i, y))
        else:
            break


    for i in range(x-1, max(x-k-1, -1), -1):
        if g[i][y] == "@":
            break
        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
            q.append((i, y))
        else:
            break

    for j in range(y+1, min(y+k+1, w)):
        if g[x][j] == "@":
            break
        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
            q.append((x, j))
        else:
            break


    for j in range(y-1, max(y-k-1, -1), -1):
        if g[x][j] == "@":
            break
        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
            q.append((x, j))
        else:
            break

if dp[x2-1][y2-1] == inf:
    print(-1)
else:
    print(dp[x2-1][y2-1])


Fixed submission:
from collections import deque
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

inf = 10**9
dp = [[inf for j in range(w)] for k in range(h)]
dp[x1-1][y1-1] = 0
q = deque([(x1-1, y1-1)])

while q:
    x, y = q.popleft()
    if (x, y) == (x2-1, y2-1):
        break
    c = dp[x][y]
    for i in range(x+1, min(x+k+1, h)):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break


    for i in range(x-1, max(x-k-1, -1), -1):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break

    for j in range(y+1, min(y+k+1, w)):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break


    for j in range(y-1, max(y-k-1, -1), -1):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break

if dp[x2-1][y2-1] == inf:
    print(-1)
else:
    print(dp[x2-1][y2-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

inf = 10**9
dp = [[inf for j in range(w)] for k in range(h)]
dp[x1-1][y1-1] = 0
q = deque([(x1-1, y1-1)])

while q:
    x, y = q.popleft()
    if (x, y) == (x2-1, y2-1):
        break
    c = dp[x][y]
    for i in range(x+1, x+k+1):
        if 0 <= i <= h-1:
            if g[i][y] == "@":
                break
            if dp[i][y] >= c + 1:
                dp[i][y] = c + 1
                q.append((i, y))
            else:
                break
        else:
            break

    for i in range(x-1, x-k-1, -1):
        if 0 <= i <= h-1:
            if g[i][y] == "@":
                break
            if dp[i][y] >= c + 1:
                dp[i][y] = c + 1
                q.append((i, y))
            else:
                break
        else:
            break

    for j in range(y+1, y+k+1):
        if 0 <= j <= w-1:
            if g[x][j] == "@":
                break
            if dp[x][j] >= c + 1:
                dp[x][j] = c + 1
                q.append((x, j))
            else:
                break
        else:
            break

    for j in range(y-1, y-k-1, -1):
        if 0 <= j <= w-1:
            if g[x][j] == "@":
                break
            if dp[x][j] >= c + 1:
                dp[x][j] = c + 1
                q.append((x, j))
            else:
                break
        else:
            break

if dp[x2-1][y2-1] == inf:
    print(-1)
else:
    print(dp[x2-1][y2-1])


Fixed submission:
from collections import deque
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

inf = 10**9
dp = [[inf for j in range(w)] for k in range(h)]
dp[x1-1][y1-1] = 0
q = deque([(x1-1, y1-1)])

while q:
    x, y = q.popleft()
    if (x, y) == (x2-1, y2-1):
        break
    c = dp[x][y]
    for i in range(x+1, min(x+k+1, h)):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break


    for i in range(x-1, max(x-k-1, -1), -1):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break

    for j in range(y+1, min(y+k+1, w)):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break


    for j in range(y-1, max(y-k-1, -1), -1):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break

if dp[x2-1][y2-1] == inf:
    print(-1)
else:
    print(dp[x2-1][y2-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

inf = 10**18
dp = [[inf for j in range(w)] for k in range(h)]
dp[x1-1][y1-1] = 0
q = deque([(x1-1, y1-1)])

while q:
    x, y = q.popleft()
    for i in range(x+1, x+k+1):
        if 0 <= i <= h-1:
            if g[i][y] == "@":
                break
            if dp[i][y] >= dp[x][y] + 1:
                dp[i][y] = dp[x][y] + 1
                q.append((i, y))
            else:
                break
        else:
            break

    for i in range(x-1, x-k-1, -1):
        if 0 <= i <= h-1:
            if g[i][y] == "@":
                break
            if dp[i][y] >= dp[x][y] + 1:
                dp[i][y] = dp[x][y] + 1
                q.append((i, y))
            else:
                break
        else:
            break

    for j in range(y+1, y+k+1):
        if 0 <= j <= w-1:
            if g[x][j] == "@":
                break
            if dp[x][j] >= dp[x][y] + 1:
                dp[x][j] = dp[x][y] + 1
                q.append((x, j))
            else:
                break
        else:
            break

    for j in range(y-1, y-k-1, -1):
        if 0 <= j <= w-1:
            if g[x][j] == "@":
                break
            if dp[x][j] >= dp[x][y] + 1:
                dp[x][j] = dp[x][y] + 1
                q.append((x, j))
            else:
                break
        else:
            break

if dp[x2-1][y2-1] == inf:
    print(-1)
else:
    print(dp[x2-1][y2-1])


Fixed submission:
from collections import deque
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

inf = 10**9
dp = [[inf for j in range(w)] for k in range(h)]
dp[x1-1][y1-1] = 0
q = deque([(x1-1, y1-1)])

while q:
    x, y = q.popleft()
    if (x, y) == (x2-1, y2-1):
        break
    c = dp[x][y]
    for i in range(x+1, min(x+k+1, h)):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break


    for i in range(x-1, max(x-k-1, -1), -1):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break

    for j in range(y+1, min(y+k+1, w)):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break


    for j in range(y-1, max(y-k-1, -1), -1):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break

if dp[x2-1][y2-1] == inf:
    print(-1)
else:
    print(dp[x2-1][y2-1])

Buggy python submission (verdict: Time Limit Exceeded):
from collections import deque
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

#dp[i][j][direction] = (count, rem)
inf = 10**18
dp = [[[(inf, inf) for i in range(4)] for j in range(w)] for k in range(h)]

q = deque([((0, 0), x1-1, y1-1, i) for i in range(4)])
used = [[[False for l in range(4)] for i in range(w)] for j in range(h)]

for i in range(4):
    dp[x1-1][y1-1][i] = (0, 0)

while q:
    count, x, y, d = q.popleft()
    for dx, dy, dd in [(-1, 0, 2), (1, 0, 0), (0, -1, 1), (0, 1, 3)]:
        if 0 <= x+dx <= h-1 and 0 <= y+dy <= w-1:
            if g[x+dx][y+dy] == "@":
                continue

            if dd == d:
                if count[1] == k-1:
                    nextcount = (count[0]+1, 0)
                else:
                    nextcount = (count[0], count[1]+1)

            else:
                nextcount = (count[0]+1, 0)

            if dp[x+dx][y+dy][dd] < nextcount:
                continue
            dp[x+dx][y+dy][dd] = nextcount
            q.append((nextcount, x+dx, y+dy, dd))


ans = inf
for i in range(4):
    temp = dp[x2-1][y2-1][i][0]
    if dp[x2-1][y2-1][i][1] > 0:
        temp += 1
    ans = min(ans, temp)

if ans >= inf:
    ans = -1
print(ans)


Fixed submission:
from collections import deque
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

inf = 10**9
dp = [[inf for j in range(w)] for k in range(h)]
dp[x1-1][y1-1] = 0
q = deque([(x1-1, y1-1)])

while q:
    x, y = q.popleft()
    if (x, y) == (x2-1, y2-1):
        break
    c = dp[x][y]
    for i in range(x+1, min(x+k+1, h)):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break


    for i in range(x-1, max(x-k-1, -1), -1):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break

    for j in range(y+1, min(y+k+1, w)):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break


    for j in range(y-1, max(y-k-1, -1), -1):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break

if dp[x2-1][y2-1] == inf:
    print(-1)
else:
    print(dp[x2-1][y2-1])

Buggy python submission (verdict: Time Limit Exceeded):
from heapq import *
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

#dp[i][j][direction] = (count, rem)
inf = 10**18
dp = [[[(inf, inf) for i in range(4)] for j in range(w)] for k in range(h)]

q = [((0, 0), x1-1, y1-1, i) for i in range(4)]
used = [[[False for l in range(4)] for i in range(w)] for j in range(h)]

for i in range(4):
    dp[x1-1][y1-1][i] = (0, 0)

while q:
    count, x, y, d = heappop(q)
    if used[x][y][d]:
        continue
    if x == x2 and y == y2:
        break
    used[x][y][d] = True

    for dx, dy, dd in [(-1, 0, 2), (1, 0, 0), (0, -1, 1), (0, 1, 3)]:
        if 0 <= x+dx <= h-1 and 0 <= y+dy <= w-1:
            if g[x+dx][y+dy] == "@":
                continue

            if dd == d:
                if count[1] == k-1:
                    nextcount = (count[0]+1, 0)
                else:
                    nextcount = (count[0], count[1]+1)

            else:
                nextcount = (count[0]+1, 0)

            if dp[x+dx][y+dy][dd] <= nextcount:
                continue
            dp[x+dx][y+dy][dd] = nextcount
            heappush(q, (nextcount, x+dx, y+dy, dd))

ans = inf
for i in range(4):
    temp = dp[x2-1][y2-1][i][0]
    if dp[x2-1][y2-1][i][1] > 0:
        temp += 1
    ans = min(ans, temp)

if ans >= inf:
    ans = -1
print(ans)


Fixed submission:
from collections import deque
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

inf = 10**9
dp = [[inf for j in range(w)] for k in range(h)]
dp[x1-1][y1-1] = 0
q = deque([(x1-1, y1-1)])

while q:
    x, y = q.popleft()
    if (x, y) == (x2-1, y2-1):
        break
    c = dp[x][y]
    for i in range(x+1, min(x+k+1, h)):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break


    for i in range(x-1, max(x-k-1, -1), -1):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break

    for j in range(y+1, min(y+k+1, w)):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break


    for j in range(y-1, max(y-k-1, -1), -1):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break

if dp[x2-1][y2-1] == inf:
    print(-1)
else:
    print(dp[x2-1][y2-1])

Buggy python submission (verdict: Time Limit Exceeded):
from heapq import *
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

#dp[i][j][direction] = (count, rem)
inf = 10**18
dp = [[[(inf, inf) for i in range(4)] for j in range(w)] for k in range(h)]

q = [((0, 0), x1-1, y1-1, i) for i in range(4)]
used = [[[False for l in range(4)] for i in range(w)] for j in range(h)]

for i in range(4):
    dp[x1-1][y1-1][i] = (0, 0)

while q:
    count, x, y, d = heappop(q)
    if used[x][y][d]:
        continue
    used[x][y][d] = True

    for dx, dy, dd in [(-1, 0, 2), (1, 0, 0), (0, -1, 1), (0, 1, 3)]:
        if 0 <= x+dx <= h-1 and 0 <= y+dy <= w-1:
            if g[x+dx][y+dy] == "@":
                continue

            if dd == d:
                if count[1] == k-1:
                    nextcount = (count[0]+1, 0)
                else:
                    nextcount = (count[0], count[1]+1)

            else:
                nextcount = (count[0]+1, 0)

            if dp[x+dx][y+dy][dd] < nextcount:
                continue
            dp[x+dx][y+dy][dd] = nextcount
            heappush(q, (nextcount, x+dx, y+dy, dd))

ans = inf
for i in range(4):
    temp = dp[x2-1][y2-1][i][0]
    if dp[x2-1][y2-1][i][1] > 0:
        temp += 1
    ans = min(ans, temp)

if ans >= inf:
    ans = -1
print(ans)


Fixed submission:
from collections import deque
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

inf = 10**9
dp = [[inf for j in range(w)] for k in range(h)]
dp[x1-1][y1-1] = 0
q = deque([(x1-1, y1-1)])

while q:
    x, y = q.popleft()
    if (x, y) == (x2-1, y2-1):
        break
    c = dp[x][y]
    for i in range(x+1, min(x+k+1, h)):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break


    for i in range(x-1, max(x-k-1, -1), -1):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break

    for j in range(y+1, min(y+k+1, w)):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break


    for j in range(y-1, max(y-k-1, -1), -1):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break

if dp[x2-1][y2-1] == inf:
    print(-1)
else:
    print(dp[x2-1][y2-1])

Buggy python submission (verdict: Time Limit Exceeded):
from heapq import *
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

#dp[i][j][direction] = (count, rem)
inf = 10**18
dp = [[[(inf, inf) for i in range(4)] for j in range(w)] for k in range(h)]

q = [((0, 0), x1-1, y1-1, i) for i in range(4)]
for i in range(4):
    dp[x1-1][y1-1][i] = (0, 0)

while q:
    count, x, y, d = heappop(q)
    if count != dp[x][y][d]:
        continue

    for dx, dy, dd in [(-1, 0, 2), (1, 0, 0), (0, -1, 1), (0, 1, 3)]:
        if 0 <= x+dx <= h-1 and 0 <= y+dy <= w-1:
            if g[x+dx][y+dy] == "@":
                continue

            if dd == d:
                if count[1] == k-1:
                    nextcount = (count[0]+1, 0)
                else:
                    nextcount = (count[0], count[1]+1)

            else:
                nextcount = (count[0]+1, 0)

            if dp[x+dx][y+dy][dd] < nextcount:
                continue
            dp[x+dx][y+dy][dd] = nextcount
            heappush(q, (nextcount, x+dx, y+dy, dd))

ans = inf
for i in range(4):
    temp = dp[x2-1][y2-1][i][0]
    if dp[x2-1][y2-1][i][1] > 0:
        temp += 1
    ans = min(ans, temp)

if ans >= inf:
    ans = -1
print(ans)


Fixed submission:
from collections import deque
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

inf = 10**9
dp = [[inf for j in range(w)] for k in range(h)]
dp[x1-1][y1-1] = 0
q = deque([(x1-1, y1-1)])

while q:
    x, y = q.popleft()
    if (x, y) == (x2-1, y2-1):
        break
    c = dp[x][y]
    for i in range(x+1, min(x+k+1, h)):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break


    for i in range(x-1, max(x-k-1, -1), -1):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break

    for j in range(y+1, min(y+k+1, w)):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break


    for j in range(y-1, max(y-k-1, -1), -1):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break

if dp[x2-1][y2-1] == inf:
    print(-1)
else:
    print(dp[x2-1][y2-1])

Buggy python submission (verdict: Time Limit Exceeded):
from heapq import *
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

#dp[i][j][direction] = (count, rem)
inf = 10**18
dp = [[[(inf, inf) for i in range(4)] for j in range(w)] for k in range(h)]

q = [((0, 0), x1-1, y1-1, i) for i in range(4)]
while q:
    count, x, y, d = heappop(q)
    for dx, dy, dd in [(-1, 0, 2), (1, 0, 0), (0, -1, 1), (0, 1, 3)]:
        if 0 <= x+dx <= h-1 and 0 <= y+dy <= w-1:
            if g[x+dx][y+dy] == "@":
                continue

            if dd == d:
                if count[1] == k-1:
                    nextcount = (count[0]+1, 0)
                else:
                    nextcount = (count[0], count[1]+1)

            else:
                nextcount = (count[0]+1, 0)

            if dp[x+dx][y+dy][dd] > nextcount:
                dp[x+dx][y+dy][dd] = nextcount
                heappush(q, (nextcount, x+dx, y+dy, dd))

ans = inf
for i in range(4):
    temp = dp[x2-1][y2-1][i][0]
    if dp[x2-1][y2-1][i][1] > 0:
        temp += 1
    ans = min(ans, temp)

if ans >= inf:
    ans = -1
print(ans)


Fixed submission:
from collections import deque
h, w, k = map(int, input().split())
x1, y1, x2, y2 = map(int, input().split())

g = []
for i in range(h):
    g.append(input())

inf = 10**9
dp = [[inf for j in range(w)] for k in range(h)]
dp[x1-1][y1-1] = 0
q = deque([(x1-1, y1-1)])

while q:
    x, y = q.popleft()
    if (x, y) == (x2-1, y2-1):
        break
    c = dp[x][y]
    for i in range(x+1, min(x+k+1, h)):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break


    for i in range(x-1, max(x-k-1, -1), -1):
        if g[i][y] == "@":
            break

        if dp[i][y] == inf:
           q.append((i, y))

        if dp[i][y] >= c + 1:
            dp[i][y] = c + 1
        else:
            break

    for j in range(y+1, min(y+k+1, w)):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break


    for j in range(y-1, max(y-k-1, -1), -1):
        if g[x][j] == "@":
            break

        if dp[x][j] == inf:
            q.append((x, j))

        if dp[x][j] >= c + 1:
            dp[x][j] = c + 1
        else:
            break

if dp[x2-1][y2-1] == inf:
    print(-1)
else:
    print(dp[x2-1][y2-1])