^7的正整数。
</div></div></div></div></div><div class="row"><div class="column"><h4 class="ui top attached block header">输出格式</h4><div class="ui bottom attached segment font-content"><div style="position: relative; overflow: hidden;"><div class=content>最小的距离。


</div></div></div></div></div><div class="row"><div class="column"><h4 class="ui top attached block header">样例</h4><div class="ui bottom attached segment font-content"><div style="position: relative; overflow: hidden;