#!/usr/bin/perl
#abc85_d.pl
#Sun Jan  7 20:56:39 2018
#

use warnings;
use strict;

my $fir = <STDIN>;
chomp $fir;

my @temp = split(" ",$fir);

my $n = $temp[0];
my $h = $temp[1];

my $loopnum = $n;

my @cut;
my @throw;

while ($loopnum > 0){
	my $stdin = <STDIN>;
	chomp $stdin;
	my @temp = split(" ",$stdin);
	push (@cut, $temp[0]);
	push (@throw, $temp[1]);
	$loopnum--;
}

my $mincut = 10000000000;

my @cutsorted = sort {$b <=> $a} @cut;

my $thrownum;
my $throwdamage = 0;

foreach (@throw){
	if ($cutsorted[0] <= $_){
		$thrownum++;
		$throwdamage = $throwdamage+$_;
	}
}

if ($throwdamage > $h){
	my @throwsorted = sort {$b <=> $a} @throw;
	my $throwcount = 1;
	foreach (@throwsorted){
		$h = $h - $_;
#		print "HP: ${h}\n";
		if ($h <= 0){
			print $throwcount,"\n";
			last;
		}
		$throwcount++;
	}
	print $throwcount,"\n";
}else{	
	my $cutnum = int(($h - $throwdamage)/$cutsorted[0]);
	if (($h - $throwdamage)%$cutsorted[0]>0){
		$cutnum++;
	}
	print $cutnum+$thrownum,"\n";
}



