{"raw_statement":[{"iden":"problem statement","content":"There are $N$ cities on a number line. The $i$\\-th city is located at coordinate $x_i$.\nYour objective is to visit all these cities at least once.\nIn order to do so, you will first set a positive integer $D$.\nThen, you will depart from coordinate $X$ and perform Move $1$ and Move $2$ below, as many times as you like:\n\n*   Move $1$: travel from coordinate $y$ to coordinate $y + D$.\n*   Move $2$: travel from coordinate $y$ to coordinate $y - D$.\n\nFind the maximum value of $D$ that enables you to visit all the cities.\nHere, to visit a city is to travel to the coordinate where that city is located."},{"iden":"constraints","content":"*   All values in input are integers.\n*   $1 \\leq N \\leq 10^5$\n*   $1 \\leq X \\leq 10^9$\n*   $1 \\leq x_i \\leq 10^9$\n*   $x_i$ are all different.\n*   $x_1, x_2, ..., x_N \\neq X$"},{"iden":"input","content":"Input is given from Standard Input in the following format:\n\n$N$ $X$\n$x_1$ $x_2$ $...$ $x_N$"},{"iden":"sample input 1","content":"3 3\n1 7 11"},{"iden":"sample output 1","content":"2\n\nSetting $D = 2$ enables you to visit all the cities as follows, and this is the maximum value of such $D$.\n\n*   Perform Move $2$ to travel to coordinate $1$.\n*   Perform Move $1$ to travel to coordinate $3$.\n*   Perform Move $1$ to travel to coordinate $5$.\n*   Perform Move $1$ to travel to coordinate $7$.\n*   Perform Move $1$ to travel to coordinate $9$.\n*   Perform Move $1$ to travel to coordinate $11$."},{"iden":"sample input 2","content":"3 81\n33 105 57"},{"iden":"sample output 2","content":"24"},{"iden":"sample input 3","content":"1 1\n1000000000"},{"iden":"sample output 3","content":"999999999"}],"translated_statement":null,"sample_group":[],"show_order":["default"],"formal_statement":null,"simple_statement":null,"has_page_source":true}