import sys
input=sys.stdin.readline
n,hp=map(int,input().split())
ata,sute=zip(*[tuple(map(int,input().split())) for i in range(n)])
ata=max(ata)
sute=sorted(list(sute),reverse=1)

ans=float("inf")
for i in range(n):
    hp-=sute[i]
    ans=min(ans,-(-max(0,hp)//ata)+i+1)
print(ans)