n, H = map(int, input().split())
a = []
b = []
for i in range(n):
    ai, bi = map(int, input().split())
    a.append(ai)
    b.append(bi)

ans = 0
amax = max(a)
b.sort(reverse=True)
# print(amax, b)
i = 0
while H > 0:
    if amax < b[i]:
        H -= b[i]
        ans += 1
        i += 1
    else:
        ans += H//amax
        if H%amax != 0:
            ans += 1
        break

print(ans)