10214

类似 https://www.cnblogs.com/towboa/p/17303216.html , 不过给的是n ,m (n<=2000) 枚举 i (1<=i<=n) ，考虑 有多少 j （1<=j<=m) gcd__(i,j)==0 然后分段考虑 (gcd(x,y) = gcd(x,y-x) ......