N, H = map(int, input().split())
A = []
B = []
for i in range(N):
    a, b = map(int, input().split())
    A.append(a)
    B.append(b)

sum_b = sum(B)

ans = 0
s = 0
if sum_b >= H:
    for i in range(N):
        s += B[i]
        if s >= H:
            print(i+1)
            exit()

max_a = 0
for i in range(N):
    if A[max_a] < A[i]:
        max_a = i

nokori = H - sum_b

if nokori % A[max_a] == 0:
    ans = nokori // A[max_a] + len(B)
else:
    ans = nokori // A[max_a] + len(B) + 1



print(ans)
