n, h = map(int,input().split())

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

A = sorted(A)
B = sorted(B)

for i in range(n):
    if A[-1] > B[i]:
        continue
    else:
        break

if A[-1] > B[-1]:
    h = h
else:
    h = h - sum(B[i:])
    t += n - i

t += h//A[-1] if h%A[-1] == 0 else h//A[-1] + 1

print(t)