from math import ceil
N, H = map(int, input().split())
a = [list(map(int, input().split()))for _ in range(N)]
a.sort(key=lambda x: x[1])
s = 0
ans = 0
m = max(a, key=lambda x: x[0])[0]
for n in a:
    if m < n[1]:
        s += n[1]
        ans += 1
        if s >= H:
            break
else:
    ans += ceil((H - s) / max(a, key=lambda x: x[0])[0])
print(ans)
