(1/2+1/3+……+1/1997)(1+1/2+……1/1996)-(1+1/2+……+1/1997)(1/2+1/3+……+1/1996)='a7G(O9J-_7k;C'X5x/_3w(z8n*N7t7i*b'S(_2q/q7b:U0C,r
算式:提示*O;z*O1[+i;P;a6Q0V7t7i*b'S(_2q/q7b:U0C,r