N,H = map(int,input().split())
A = [-1 for _ in range(N)]
B = [-1 for _ in range(N)]
for i in range(N):
    a,b = map(int,input().split())
    A[i] = a
    B[i] = b
MA = max(A)
B.sort(reverse=True)
ans = 0

idx = 0
while H > 0 and idx <= N-1:
    if B[idx] > MA:
        H -= B[idx]
        idx += 1
        ans += 1
    else:
        ans += (H+MA-1)//MA
        H = 0
        break

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