n,h = map(int,input().split())
lst = []
amax = 0
for i in range(n):
    a,b = map(int,input().split())
    amax = max(amax,a)
    lst.append([a,b])
lst.sort(key = lambda x:x[1],reverse = True)
dmg = 0
cnt = 0
for i in range(n):
    cnt += 1
    dmg += lst[i][1]
    if dmg >= h:
        print(cnt)
        break
else:
    while dmg<h:
        dmg += amax
        cnt += 1
print(cnt-1)