n,h = map(int, raw_input().split())
l = [map(int, raw_input().split()) for _ in range(n)]
m = []
for a,b in l:
    m.append((b,0))
    m.append((a,1))
m.sort()
m.reverse()
i = 0
while h > 0 and m[i][1] == 0:
    h -= m[i][0]
    i += 1
if h <= 0:
    print i
else:
    print i + (h + m[i][0] - 1) / m[i][0]
