←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
x
←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
←
→
x
x
x
←
→
x
←
→
x
x
←
→
x
x
x
x
x
x
x
x
x
x
x
←
→
x
←
→
x
←
→
x