n,h=map(int,input().split())
a=[]
b=[]
count=0
for i in range(n):
    ai,bi=map(int,input().split())
    a.append(ai)
    b.append(bi)
last_i=a.index(max(a))
b=[i for i in b if i>=a[last_i]]
sum_b=sum(b)
if sum_b<h:
    count+=len(b)
    tmp=(h-sum_b)/a[last_i]
    tm=(h-sum_b)%a[last_i]
    count+=int(tmp)+1 if tm!=0 else int(tmp)
else:
    b=sorted(b)
    for i in range(len(b)):
        if sum(b[i:])<h:
            count+=i+1
            break

print(count)