n,h=map(int,input().split())
x=[0]*n
y=0
for i in range(n):
    a,b=map(int,input().split())
    y=max(y,a)
    x[i]=b
cnt=0
x.sort(reverse=1)
for i in x:
    if i>y:
        cnt+=1
        h-=i
    if h<=0:
        print(cnt)
        exit()
print(cnt+(h+y-1)//y)