N,H = map(int,input().split())
ab = [list(map(int,input().split())) for i in range(N)]
ab.sort(key=lambda x: x[1])
ab.sort(reverse=True,key=lambda x: x[0])
A,B = ab[0]
ab.sort(reverse=True,key=lambda x: x[1])
ans = 0
i=0
while i<N:
    if H<=0:
        break
    if A == ab[i][0] and ab[i][1]==B:
        i+= 1
        continue
    if ab[i][1]>A:
        H-=ab[i][1]
        i+= 1
        ans += 1
        continue
    else:
        break
from math import ceil
if H>0:
    if H<=B:
        ans += 1
    else:
        ans += 1+ceil((H-B)/A)
print(ans)
