from math import ceil
n, h = map(int, input().split())
a = []
b = []
for i in range(n):
    ai, bi = map(int,input().split())
    a.append(ai)
    b.append(bi)

ans = 0
b = sorted(b, reverse=True)
maxa = max(a)
b2 = [i for i in b if i > maxa]
ans += len(b2)
h2 = h - sum(b2)
if h2 > 0:
    ans += ceil(h2/maxa)
print(ans)