import math
N,H=(int(x) for x in input().split())
a=[]
b=[]
for n in range(N):
    aa,bb=(int(x) for x in input().split())
    a.append(aa)
    b.append(bb)
b_sort=sorted(b)
a_sort=sorted(a)
count=0
for n in range(N):
    if b[n]>a_sort[N-1]:
        H=H-b[n]
        count+=1
        if H<=0:
            break
if H>0:
    count=count+math.ceil(H/a_sort[N-1])
print(count)
