<span style="font-family:宋体;">现代数学的著名证明之一是</span><span>Georg Cantor</span><span style="font-family:宋体;">证明了有理数是可枚举的。他是用下面这一张表来证明这一命题的：</span> 

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					<span>1/1<span>&nbsp; </span>1/2 <span>&nbsp;</span>1/3 <span>&nbsp;</span>1/4 <span>&nbsp;</span>1/5 </span><span style="font-family:宋体;">…</span> 
				</p>
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					<span>2/1 <span>&nbsp;</span>2/2 <span>&nbsp;</span>2/3 <span>&nbsp;</span>2/4 <span>&nbsp;</span></span><span style="font-family:宋体;">…</span> 
				</p>
				<p class="MsoNormal">
					<span>3/1 <span>&nbsp;</span>3/2 <span>&nbsp;</span>3/3 <span>&nbsp;</span></span><span style="font-family:宋体;">…</span> 
				</p>
				<p class="MsoNormal">
					<span>4/1 <span>&nbsp;</span>4/2 <span>&nbsp;</span></span><span style="font-family:宋体;">…</span> 
				</p>
				<p class="MsoNormal">
					<span>5/1 <span>&nbsp;</span></span><span style="font-family:宋体;">…</span> 
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				<p class="MsoNormal">
					<span style="font-family:宋体;">…</span> 
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<span> 
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				<div class="shape">
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						<span>1/1<span>&nbsp; </span>1/2 <span>&nbsp;</span>1/3 <span>&nbsp;</span>1/4 <span>&nbsp;</span>1/5 </span><span style="font-family:宋体;">…</span> 
					</p>
					<p class="MsoNormal">
						<span>2/1 <span>&nbsp;</span>2/2 <span>&nbsp;</span>2/3 <span>&nbsp;</span>2/4 <span>&nbsp;</span></span><span style="font-family:宋体;">…</span> 
					</p>
					<p class="MsoNormal">
						<span>3/1 <span>&nbsp;</span>3/2 <span>&nbsp;</span>3/3 <span>&nbsp;</span></span><span style="font-family:宋体;">…</span> 
					</p>
					<p class="MsoNormal">
						<span>4/1 <span>&nbsp;</span>4/2 <span>&nbsp;</span></span><span style="font-family:宋体;">…</span> 
					</p>
					<p class="MsoNormal">
						<span>5/1 <span>&nbsp;</span></span><span style="font-family:宋体;">…</span> 
					</p>
					<p class="MsoNormal">
						<span style="font-family:宋体;">…</span> 
					</p>
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						<span></span>
					</p>
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		</tr>
	</tbody>
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<span></span>

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<span></span>

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<span><span>&nbsp;&nbsp;&nbsp; </span></span><span style="font-family:宋体;">我们以</span><span>Z</span><span style="font-family:宋体;">字形给上表的每一项编号。第一项是</span><span>1/1</span><span style="font-family:宋体;">，然后是</span><span>1/2</span><span style="font-family:宋体;">，</span><span>2/1</span><span style="font-family:宋体;">，</span><span>3/1</span><span style="font-family:宋体;">，</span><span>2/2</span><span style="font-family:宋体;">，…</span> 

<span><span>&nbsp;&nbsp;&nbsp; </span></span><span style="font-family:宋体;">输入：整数</span><span>N</span><span style="font-family:宋体;">（</span><span>1</span><span style="font-family:宋体;">≤</span><span>N</span><span style="font-family:宋体;">≤</span><span>10000000</span><span style="font-family:宋体;">）</span><span><span>&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="font-family:宋体;">输出：表中的第</span><span>N</span><span style="font-family:宋体;">项</span> 

<span><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="font-family:宋体;">样例：</span><span><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>INPUT<span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>OUTPUT</span> 

<span><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="font-family:宋体;">　　　　　　　</span><span>N=7<span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span>1/4</span>