13334: 线段上点的个数

Memory Limit:64 MB Time Limit:1.000 S
Judge Style:Text Compare Creator:
Submit:2 Solved:0

Description

给定平面上两个点p1=(x1,y1),p2=(x2,y2),线段p1p2上,除p1和p2以外一共有几个格点(即坐标为整数的点)?

限制条件,-10^9<=x1,x2,y1,y2<=10^9

Input

每一行输入x1,y1,x2,y2,以空格隔开;

Output

对应的每一行输出格点数

Sample Input Copy

1 11 5 3

Sample Output Copy

3