N, H = map(int, input().split())
a_list = []
b_list = []
for i in range(N):
    a, b = map(int, input().split())
    a_list.append(a)
    b_list.append(b)
count = 0
a = max(a_list)
b_list.sort()
while True:
    if len(b_list) >= 1:
        if b_list[-1] >= a:
            b = b_list.pop(-1)
            H -= b
            count += 1
            if H <= 0:
                print(count)
                exit()
        else:
            break
print(count + H // a+ 1)