{"trustable":false,"prependHtml":"\u003cscript\u003e window.katexOptions \u003d { disable: true }; \u003c/script\u003e\n\u003cscript type\u003d\"text/x-mathjax-config\"\u003e\n MathJax.Hub.Config({\n tex2jax: {\n inlineMath: [[\u0027$$$\u0027,\u0027$$$\u0027], [\u0027$\u0027,\u0027$\u0027]],\n displayMath: [[\u0027$$$$$$\u0027,\u0027$$$$$$\u0027], [\u0027$$\u0027,\u0027$$\u0027]]\n }\n });\n\u003c/script\u003e\n\u003cscript async src\u003d\"https://mathjax.codeforces.org/MathJax.js?config\u003dTeX-AMS-MML_HTMLorMML\" type\u003d\"text/javascript\"\u003e\u003c/script\u003e","sections":[{"title":"","value":{"format":"HTML","content":"\u003cscript type\u003d\u0027text/x-mathjax-config\u0027\u003eMathJax.Hub.Config({tex2jax: { inlineMath: [[\u0027$\u0027,\u0027$\u0027]] } }); \u003c/script\u003e\n\u003cscript type\u003d\u0027text/javascript\u0027 src\u003d\u0027https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config\u003dTeX-AMS-MML_HTMLorMML\u0027\u003e\u003c/script\u003e\n\u003cscript type\u003d\u0027text/javascript\u0027\u003esetTimeout(function(){MathJax.Hub.Queue([\u0027Typeset\u0027, MathJax.Hub, \u0027left_view\u0027]);}, 2000);\u003c/script\u003e\n\u003cdiv class\u003d\"panel_content\"\u003e\nGiven set A and B, your task is to calculate A - B, which is defined as {a |a∈A, a ∉ B}\n "}},{"title":"Input","value":{"format":"HTML","content":"The input consists of several test cases.\n\u003cbr\u003e\nEvery test case contains n(0\u0026lt;\u003dn\u0026lt;\u003d100, n is an integer) and m(0\u0026lt;\u003dm\u0026lt;\u003d100,m is an integer),indicating the number of elements of set A and B.\n\u003cbr\u003e\nThen follows n + m integers, indicating the elements of A and B, the elements from A come first. The elements are seperated with spaces.\n\u003cbr\u003e\nIf n and m all equal to 0, the input ends.\n\u003cbr\u003e\nAll integers are in the range of [-2 ^ 31,2 ^ 31 - 1] \n\u003cbr\u003e"}},{"title":"Output","value":{"format":"HTML","content":"For each test case, print the result of A - B in one line, if there is no element in A - B, print \"NULL\", else print the answer in an ascending order.\n\u003cbr\u003e\nElements shall be seperated with spaces.\n\u003cbr\u003e"}},{"title":"Sample Input","value":{"format":"HTML","content":"\u003cpre\u003e3 3 1 2 3 1 4 7\n3 7 2 5 8 2 3 4 5 6 7 8 \n0 0\u003c/pre\u003e"}},{"title":"Sample Output","value":{"format":"HTML","content":"\u003cpre\u003e2 3 \nNULL\u003c/pre\u003e"}}]}