n,h=map(int,input().split())
a=[0]*n
b=[0]*n
for i in range(n)
a[i],b[i]=map(int,input().split()) 
x=max((a))
y=[i for i in b if i>A]
y.sort(reverse=True)
count=0
for i in range(len(y)):
    if h>0:
        count+=1
        h-=y[i]
    else:
        break
 if h>0:
     count +=int(h//x)+1
print(count)