n,h=map(int,input().split())
a_m=0
b_list=[]
for i in range(n):
    a,b=map(int,input().split())
    a_m=max(a_m,a)
    b_list.append(b)
b_list.sort(reverse=True)
Sum=0
count=0
for i in range(n):
    if b_list[i]>=a_m:
        Sum=Sum+b_list[i]
        count=count+1
    else:
        break
ans=count+((h-Sum)+a_m-1)//a_m
print(ans)
