A triangle field is numbered with successive integers in the way shown on the picture below. 



The traveller needs to go from the cell with number M to the cell with number N. The traveller is able to enter the cell through cell edges only, he can not travel from cell to cell through vertices. The number of edges the traveller passes makes the length of the traveller‘s route. 

Write the program to determine the length of the shortest route connecting cells with numbers N and M. 

Input contains two integer numbers M and N in the range from 1 to 1000000000 separated with space(s).

Output should contain the length of the shortest route.

我们把上下两个相连的三角形构成的菱形看做一个格，左斜线看做横坐标，右斜线看做纵坐标，也是四个方向(0,-1),(0,1),(-1,0),(1,0)变化，那么就相当于直角坐标了。

从(x1,y1)到(x2,y2)，这是斜角坐标，距离dis=abs(x1-x2)+abs(y1-y2);我们还需要考虑菱形中的移动，这个都是一层移动一次。

所以答案ans=dis+abs(a-b)=abs(x1-x2)+abs(y1-y2)+abs(a-b)，其中a和b表示各自层数，x1,y1,x2,y2表示两个数所在菱形在斜角坐标系的位置。