n,h = map(int,input().split())
a = [0]*n;b = [0]*n;ma = 0;mi = 0;ls = []
for i in range(n):
    a[i],b[i] = map(int,input().split())
    ma = max(ma,a[i])
for i in range(n):
    if ma < b[i]:ls.append(b[i])
ls.sort(reverse = True);count = 0
for i in ls:
    count += 1
    h -= i
    if h < 0:break
count += h // ma
if h%ma > 0:count += 1
print(count)