1                <
20               <
301              <
4012             <
50123            <
601234           <
7012345          <
80123456         <
901234567      <
10012345670     <
110123456701    <
1201234567012   <
13012345670123  <
140123456701234 <
150123456701234 <
160123456701234 <
170123456701234 <
18