N,H = (int(i) for i in input().split())
a = []
b = [0]
for i in range(N):
    A,B = (int(i) for i in input().split())
    a.append(A)
    b.append(B)
    

count = 0
biga = max(a)
bigb = max(b)
b.sort(reverse = True)
while H > 0:
    if bigb > biga:
        H -= bigb
        b.remove(bigb)
        bigb = b[0]
    else:
        H -= biga
    count += 1

print(count)