N,H=map(int,input().split())
ab=[input().split() for i in range(N)]
a = [int(ab[i][0]) for i in range(N)]
maxa = max(a)
b = np.array([int(ab[i][1]) for i in range(N)])
b_effective = b[b > maxa]
d = 0
if sum(b_effective) < Y:
    c = len(b_effective)
    rest = H - sum(b_effective)
    if rest % maxa == 0:
        d = rest//maxa
    else:
        d = rest//maxa + 1
else:
    b = np.sort(b_effective)[::-1]
    s = 0
    for i in range(len(b)):
        s += b[i]
        if s >= Y:
            c = i + 1
            d = 0
            break
print(c+d)