import math
n , h = map(int,input().split())
max = 0
b = []
c = 0
for i in range(n):
    a , b1 = map(int,input().split())
    if a > max:
        max = a
    b.append(b1)
b.sort(reverse = True)
b.append(0)
i=0
while h > 0 and b[i]>max:
    h-=b[i]
    i+=1
    c+=1
if h > 0:
    c += math.ceil(h/max)
print(c)
