{"trustable":true,"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":"\u003cdiv class\u003d\"panel_content\"\u003eWinter is here at the North and the White Walkers are close. There\u0027s a young Night Watch standing on the Wall.\u003cbr\u003eThe young Night Watch has created a method to keep his body warm. Every time he generate a random rational number x in range $[l_i, r_i]$ independently and uniformly, then he walks x meters to east. \u003cbr\u003eNow he has n ranges $[l_1, r_1], [l_2, r_2] ... [l_n, r_n]$, He wants to know the expected distance to origin. If answer is a fraction $\\frac{p}{q}$, output an integer $0 \\leq s \u0026lt; 998244353$ so that $p \\equiv sq~(mod~998244353)$.\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"An integer n in the first line. $1 \\leq n \\leq 15$\u003cbr\u003eThe following n lines, each contain two integers $l_i, r_i$. $(-10^6 \\leq l_i \\leq r_i \\leq 10^6)$"}},{"title":"Output","value":{"format":"HTML","content":"Output the expected distance to origin in a line, modulo 998244353.\u003cbr\u003e"}},{"title":"Sample","value":{"format":"HTML","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003e2\r\n-2 3\r\n-2 1\r\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e199648872\r\n\r\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}}]}