# https://atcoder.jp/contests/abc085/tasks/abc085_d
# 5 500
# 35 44
# 28 83
# 46 62
# 31 79
# 40 43
# 9
n, h = gets.split.map(&:to_i)
a = []
b = []
n.times {
  x, y = gets.split.map(&:to_i)
  a << x
  b << y
}
max_a = a.max
count = 0
# p b.sort!.reverse!
b.each do |v|
  break if v < max_a || h <= 0
  h -= v
  count += 1
end

while h > 0
  h -= max_a
  count += 1
end
puts count