#include <iostream>#include <algorithm>#include <string.h>#include <cstdio>using namespace std;struct room{ int sta,end;}r[410];bool flag[410];int change( int num ){ if( num%2==0 ) return num/2; else return num/2+1;}bool cmp( room a,room b ){ return a.sta<b.sta;}int main(){ int T,i,j,n,last,temp; bool in; scanf( "%d",&T ); while( T-- ) { memset( flag,0,sizeof(flag) ); scanf( "%d",&n ); for( i=0;i<n;i++ ) { scanf( "%d%d",&r[i].sta,&r[i].end ); r[i].sta=change( r[i].sta ); r[i].end=change( r[i].end ); if( r[i].sta>r[i].end ) { temp=r[i].sta; r[i].sta=r[i].end; r[i].end=temp; } } sort( r,r+n,cmp ); j=0; while( 1 ) { last=-1; in=false; for( i=0;i<n;i++ ) { if( !flag[i] && r[i].sta>last ) { flag[i]=1; last=r[i].end; in=true; } } if( !in ) break; j++; } printf( "%dn",j*10 ); } return 0;}
