n, h = gets.split.map(&:to_i)

a = Array.new(n)
b = Array.new(n)
n.times do |i|
  a[i], b[i] = gets.split.map(&:to_i)
end

a.sort!
b.sort!

# p [a, b]
# p a.max

ans = 0
i = n
j = n

while a.max < b[0,j][-1] do
  
  if a[0,i][-1] < b[0,j][-1]
    
    h -= b[0, j][-1]
    j -= 1
    
  end
  ans += 1
  
  break if j == 0
  
end

puts ans + (h + a[-1] - 1 ) / a[-1]