import bisect

n, h = map(int, input().split())
a = []
b = []
for i in range(n):
    A, B = map(int, input().split())
    a.append(A)
    b.append(B)
b = sorted(b)
nage = b[bisect.bisect_right(b, max(a)):]
h -= sum(nage)
ans = len(nage)
ans += -(-h // max(a))
print(ans)