N,H = map(int,input().split())
ab = [tuple(map(int,input().split())) for i in range(N)]

maxa = max(ab)[0]
ans = 0
for a,b in sorted(ab, key=lambda x:x[1], reverse=True):
    if b <= maxa:
        break
    H -= b
    ans += 1
    if H <= 0:
        print(ans)
        exit()

ans += (H-1)//maxa + 1
print(ans)
