n,h =map(int,input().split())
a,b = [0]*n,[0]*n
for i in range(n):
    a[i],b[i] = map(int,input().split())
c = h//max(a) + [1,0][h%max(a)==0]
if sum(b) >= h:
    c0 = 1
    d = 0
    e = list(reversed(sorted(b)))
    i = 0
    while d < h:
        d += e[i] 
        c0 += 1
        i += 1
    c = min(c,c0)
print(c)