n,h=map(int,input().split())
A=[]
B=[]
C=[]
for i in range(n):
    a,b=map(int,input().split())
    A.append(a)
    B.append(b)
amax=max(A)
for i in range(n):
    if amax<=B[i]:
        C.append(B[i])
A.sort(reverse=True)
B.sort(reverse=True)
C.sort(reverse=True)
cnt=0
ans=0
i=0
for i in range(len(C)):
    if ans<h:
        ans+=C[i]
    else:
        break
    cnt+=1
if ans<h:
    cnt+=(h-ans)//amax
print(cnt)