/div></div></div><div class="row"><div class="column"><h4 class="ui top attached block header">输入格式</h4><div class="ui bottom attached segment font-content"><div style="position: relative; overflow: hidden;"><div class=content><div>The first line of the standard input contains two integers N,M(2&lt;=N&lt;=20 000,0&lt;=m&lt;=25000), separated by a single space, that specify the number of towns and roads in Byteotia respectively. The towns are numbered from &nbsp; to n. The second line of input contai