n,h = map(int, input().split())
A = 0
B = []
for _ in range(n):
    a,b = map(int, input().split())
    if A < a: A = a
    B.append(b)
B.sort(reverse=True)
hit = 0
cnt = 0
for i in range(n):
    if hit >= h: break
    if A < B[i]: 
        hit += B[i]
        cnt += 1
    else: break
if hit >= h: print(cnt)
else: print(cnt + round((h-hit)/A))