int main()
{
    int n,m=0,h=0,i;
    scanf("%d",&n);
    int a[n],b[n];
    for(i=0;i<n;i++){scanf("%d%d",&a[i],&b[i]);}
    for(i=0;i<n;i++){
                     if(a[i]>=90&&a[i]<=140&&b[i]>=60&&b[i]<=90){m=m+1;if(h<m){h=m;}
}
                     else{if(h<m){h=m;}
                          m=0;}
                    }
   printf("%d",h); 
return 0;
    }
