from collections import deque

N,H=map(int,input().split())
a=deque([]);b=deque([])
for _ in range(N):
    ai,bi=map(int,input().split())
    a.append(ai)
    b.append(bi)
bb=deque([])
for i in range(N):
    if b[i]>=max(a):
        bb.append(b[i])
if sum(bb)>=H:
    print(len(bb))
else:
    ans=int((H-sum(bb))/max(a))+len(bb)
    if (H-sum(bb))%max(a)==0:
        print(ans)
    else:
        print(ans+1)