n, h = map(int, input().split())
a = []
b = []
for i in range(n):
    ai, bi = map(int, input().split())
    a.append(ai)
    b.append(bi)
b.append(0)
b = sorted(b, reverse=True)

count = 0
while True:
    if max(b) < max(a):
        count += -(-h // max(a))
        break
    else:
        h -= b.pop(0)
        count += 1

print(count)
