n,h=map(int, input().split())
w=[]
for i in range(n):
    a,b=map(int, input().split())
    w.append([a,b])
    
w.sort(key=lambda x:x[0],reverse=True)
m=w[0][0]
w.sort(key=lambda x:x[1],reverse=True)

count=0
for i in range(n):
    if w[i][1]>=m:
        count+=1
        h -= w[i][1]
        
    if h<=0:
        print(count)
        break
else:
    
    while h>0:
        h -= m
        count+=1
print(count)