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())
    
B = sorted(B, reverse=True)
maxa = max(A)
ans = 0
for b in B:
    if b < maxa:
        break
    ans += 1
    H -= b
    if H <= 0:
        break
H = max(0, H)
ans += math.ceil(H/maxa)
print(ans)


