N,H = map(int,input().split())
a = []
b = []
for i in range(N):
    A,B=(map(int,input().split()))
    a.append(A)
    b.append(B)
count = 0
while H>0:
    if max(a)<max(b):
        count += 1
        H = H-max(b)
        b[b.index(max(b))]=0
    else:
        count += (H-1)//max(a)+1
        break
print(count)

