import sys
input = sys.stdin.readline
N,H=map(int,input().split())
A=[]
B=[]
for _ in range(N):
    a,b=map(int,input().split())
    A.append(a)
    B.append(b)


amax=max(A)
#print(amax)
b=[]
for i in range(N):
    if B[i]>=amax:
        b.append(B[i])
b.sort()
#print(b)
cnt=0
while b:
    if H>0:
        H-=b.pop()
        cnt+=1
    if H<=0:
        #print(cnt)
        exit()

cnt+=-(-H//amax)
print(cnt)
