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
while H > 0:
    bigb = max(b)
    if bigb > max(a):
        H -= bigb
        b.remove(bigb)
    else:
        H -= max(a)
    count += 1

print(count)