n,h = map(int,input().split())

A = []
B = []
for _ in range(n):
    a,b = map(int,input().split())
    A.append(a)
    B.append(b)
maxA = max(A)
B.sort(reverse=True)

cnt = 0
for i in range(n):
    if B[i] >= maxA:
        h -= B[i]
        cnt += 1
    else:
        break

if h <= 0:
    print(cnt)
elif h % maxA == 0:
    print(h//maxA + cnt)
else:
    print(h//maxA + 1 + cnt)