from math import ceil
N,H=map(int,input().split())
A,B=[],[]
for i in range(N):
    a,b=map(int,input().split())
    A.append(a);B.append(b)
B.sort(reverse=True)
sw=max(A)
cnt=0
dam=0
for i in range(N):
    if B[i]<sw:
        break
    cnt+=1
    dam+=B[i]
    if dam>=H:
        print(cnt)
        exit()
cnt+=ceil((H-dam)/sw)
print(cnt)