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([])
ma=max(a)
for i in range(N):
    bi=b[i]
    if bi>ma:
        bb.append(bi)
if sum(bb)>=H:
    print(len(bb))
else:
    ans=(H-sum(bb))/max(a)//1+len(bb)
    if (H-sum(bb))%max(a)==0:
        print(ans)
    else:
        print(ans+1)