import math
n, h = map(int, input().split())
a_max = 0
b_list = []
for i in range(n):
    a, b = map(int, input().split())
    a_max = max(a_max, a)
    b_list.append(b)
b_list = sorted(b_list, reverse=True)
count = 0
for i in range(len(b_list)):
    if a_max < b_list[i]:
        h -= b_list[i]
        count += 1
    else:
        count += math.ceil(h/a_max)
        break
print(count)
