import math
N, H = map(int, input().split())
a = [0] * N
b = [0] * N
for i in range(N):
    a[i], b[i] = map(int, input().split())

x = max(a)
b_list= []
for i in range(N):
    if b[i] > x :
        b_list.append(b[i])

y = sum(b_list)

ans = math.ceil((H-y)/x) + len(b_list)
#print(H, y, x, len(b))
#print(b_list)

print(ans)