import sys
N,H = map(int,input().split())
A = 0
B = []
for _ in range(N):
    a,b = map(int,input().split())
    A = max(A,a)
    B.append(b)
B.sort(reverse=True)

ans = 0
for b in B:
    if b > A:
        H -= b
        ans += 1
    else:
        break
    if H <= 0:
        print(ans)
        sys.exit()

print((H-1)//A +1 +ans)
