{"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\n \u003cbr\u003eSummer vacation is coming and there are more competitions to attend.\n \u003cbr\u003ebigbigfish is a active ACMer,So he wants to take part in as many competitions as possible.suppose you already know all the arrangements for the competition,Can you arrange it properly?(The aim is to participate as much as possible entire compititong)\n \u003cbr\u003e \n\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"There are multiple test cases. Each case contains a positive integer N(n\u0026lt;\u003d100)which is the total number of competitions,followed by N lines,Each line contains two number Ti_s,Ti_e (1\u0026lt;\u003di\u0026lt;\u003dn),indicates the start and end time of ith competition,n\u003d0 indicates the end of input and don’t need to processing\n\u003cbr\u003e"}},{"title":"Output","value":{"format":"HTML","content":"For each test case, output a integer in one line, indicates the total number of competitions that bigbigfish can participate , "}},{"title":"Sample Input","value":{"format":"HTML","content":"\u003cpre\u003e12\n1 3\n3 4\n0 7\n3 8\n15 19\n15 20\n10 15\n8 18\n6 12\n5 10\n4 14\n2 9\n0\u003c/pre\u003e"}},{"title":"Sample Output","value":{"format":"HTML","content":"\u003cpre\u003e5\u003c/pre\u003e"}}]}