n,h=map(int,input().split())
A,B=[],[]
for _ in range(n):
    a,b=map(int,input().split())
    A.append(a)
    B.append(b)
a=max(A)
B=sorted(list(filter(lambda x:x>a,B)),reverse=True)
ans=0
while h>0 and B:
    h-=B[0]
    B.pop(0)
    ans+=1
if h>0:
    if h%a==0:
        ans+=h//a
    else:
        ans+=(h//a+1)
print(ans)