#include<iostream>#include<cstdio>#include<cstdlib>#include<cstring>#include<algorithm>using namespace std;const int MAXN=400;struct node{ int s,t;}a[MAXN];int N;bool v[MAXN];void Solve(){ int now,Minj,ans=0; for (int i=0;i<5;i++) { memset(v,0,sizeof(v)); now=0; for (int st=i;st<=1000;st+=5) { Minj=0; for (int k=1;k<=N;k++) if (!v[k] && a[k].s<=st && st< a[k].t) if (!Minj || a[Minj].t>a[k].t) Minj=k; if (Minj) { v[Minj]=1; now++; } } if (now>ans) ans=now; } printf("%dn",ans);}int main(){ while (scanf("%d",&N),N) { for (int i=1;i<=N;i++) scanf("%d %d",&a[i].s,&a[i].t); Solve(); }}
