n,k = map(int,input().split())
L = []
for i in range(n):
    a,b = map(int,input().split())
    L.append([a,b])
L.sort(reverse = True)
#print(L)
huru = L[0][0]
L.pop(0)
L.sort(key = lambda x:x[1],reverse = True)
#print(L)
num,cnt  = 0,0
for i in range(n-1):
    if huru < L[i][1]:
        num +=L[i][1]
        cnt +=1
    #print(num,cnt)
    if num >=k:
        print(cnt)
        exit()

if (k-num)%huru == 0:
    print(cnt + (k-num)//huru)
else:
    print(cnt + (k-num)//huru+1)