= (1+1/2+1/4+1/8+1/16) + (1/3+1/6+1/12) + (1/5 + 1/10) + 1/7 + 1/9 + 1/11 + 1/13 + 1/14 + 1/15
= (2-1/16) + (1-5/12) + 3/10 +...
所以整数部分是3