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)
ma=max(a)
bs=sorted(b,reverse=True)
bc=0
c=0
for i in range(len(bs)):
    bi=b[i]
    if bi>ma:
        bc+=b[i]
        c+=1
        if H<=bc:
            print(c)
            exit()
ans=(H-bc)//ma+c
if (H-bc)%ma==0:
    print(ans)
else:
    print(ans+1)