水池何时干枯

&nbsp;<span style="font-family:宋体;font-size:12pt;">【问题描述】</span><span style="font-family:Tahoma;font-size:12pt;"><br /> </span><span style="font-family:宋体;font-size:12pt;">在西南某地山边有items水池，假设干旱出现前储水</span><span style="font-family:Tahoma;font-size:12pt;">n</span><span style="font-family:宋体;font-size:12pt;">吨！西南干旱出现了！每天附近居民用了</span><span style="font-family:Tahoma;font-size:12pt;">3</span><span style="font-family:宋体;font-size:12pt;">吨水，如果自然出水为</span><span style="font-family:Tahoma;font-size:12pt;">50</span><span style="font-family:宋体;font-size:12pt;">千克</span><span style="font-family:宋体;font-size:12pt;">！问这items水池过几天后会干枯！！</span><span style="font-family:Tahoma;font-size:12pt;"><br /> </span><span style="font-family:宋体;font-size:12pt;">【输入格式】</span><span style="font-family:Tahoma;font-size:12pt;"><br /> </span><span style="font-family:宋体;font-size:12pt;">输入一items整数</span><span style="font-family:Tahoma;font-size:12pt;">n<br /> </span><span style="font-family:宋体;font-size:12pt;">【输出格式】</span><span style="font-family:Tahoma;font-size:12pt;"><br /> </span><span style="font-family:宋体;font-size:12pt;">输出</span><span style="font-family:Tahoma;font-size:12pt;"> </span><span style="font-family:宋体;font-size:12pt;">一items整数，天数</span><span style="font-family:Tahoma;font-size:12pt;"><br /> </span><span style="font-family:宋体;font-size:12pt;">【输入样例】</span><span style="font-family:Tahoma;font-size:12pt;"><br /> 30<br /> </span><span style="font-family:宋体;font-size:12pt;">【输出样例】</span><span style="font-family:Tahoma;font-size:12pt;"><br /> 11<br /> </span><span style="font-family:宋体;font-size:12pt;">【数据规模】</span><span style="font-family:Tahoma;font-size:12pt;"><br /> 10&lt;=n&lt;=1000<br /> <br /> </span>