int main()
{
int xy[2],ok[100];
int i,n,max=0,t=0;
scanf("%d",&n);
for(i=1;i<=n;i++)
{
scanf("%d%d",&xy[0],&xy[1]);
if(xy[0]<=140&&xy[0]>=90&&xy[1]<=90&&xy[1]>=60)
ok[i]=1;
else
ok[i]=0;
}
for(i=1;i<=n;i++)
{
if(ok[i]==1)
t++;
else
t=0;
if(t>max)
max=t;
}
printf("%d",max);

return 0;
}
