import math
N,H = map(int,input().split())
src = [tuple(map(int,input().split())) for i in range(N)]
n = max(src)[0]
src.sort(key=lambda x:x[1],reverse=True)
ans = d = 0
for a,b in src:
    if b <= n: break
    d += b
    ans += 1
    if d >= H:
        print(ans)
        exit()

ans += math.ceil((H-d) / n)
print(ans)
