N, H = map(int, input().split())
maxA, B = 0, 0
rec = []

for i in range(N):
    a, b = map(int, input().split())
    rec.append((a, b))
    if a > maxA:
        maxA = a

n = N
for a, b in rec:
    if maxA > b:
        n -= 1
    else:
        B += b


ans = max((H - B) // maxA, 0)

print(ans + n)