N, H = list(map(int, input().split()))
a = []
b = []
for i in range(N):
    temp0, temp1 = list(map(int, input().split()))
    a.append(temp0)
    b.append(temp1)

b_temp = []
for i in b:
    if max(a) <= i:
        b_temp.append(i)
b = b_temp
if H <= sum(b):
    b.sort()
    b.reverse()
    for i, throw in enumerate(b):
        H -= throw
        if H <= 0:
            result = i + 1
            break
else:
    if len(b) != 0:
        H -= sum(b)
    dev = int(H / max(a))
    if H % max(a) != 0:
        dev += 1
    result = len(b) + dev

print(result)
