import math
n, h = list(map(int, input().split()))
a = []
b = []
for i in range(n):
    x, y = list(map(int, input().split()))
    a.append(x)
    b.append(y)
a = sorted(a, reverse=True)[0]
b = sorted(b, reverse=True)
count = 0
while h > 0 and b[0] > a:
    count += 1
    h -= b[0]
    b = b[1:]
    if b == []:
        break
if h > 0:
    count += math.ceil(h * 1.0 / a)
print (count)
