import heapq

n, h = map(int, input().split())
a, b = [], []
heapq.heapify(a)
heapq.heapify(b)
for _ in range(n):
    s, t = map(int, input().split())
    heapq.heappush(a, -s)
    heapq.heappush(b, -t)
m = -1 * heapq.heappop(a)
ans, c = 0, 0
while b:
    l = -1 * heapq.heappop(b)
    if l >= m and c <= h:
        ans += 1
        c += l
    elif l < m:
        ans += (h - c) // m
        if (h - c) % m != 0:
            ans += 1
        break
    else:
        break
if len(b) == 0:
    ans += (h - c) // m
    if (h - c) % m != 0:
        ans += 1
print(ans)