v>
<div align="left"><span style="font-size: medium">【样例输入2】</span></div>
<div style="text-indent: 21pt" align="left"><span style="font-size: medium">9 12 1 9</span></div>
<div style="text-indent: 21pt" align="left"><span style="font-size: medium">1 2</span></div>
<div style="text-indent: 21pt" align="left"><span style="font-size: medium">2 3</span></div>
<div style="text-indent: 21pt" align="left"><span style="font-size: medium">3 1</span></div>
<div style="text-indent: 21pt" align="left"