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
maxa = max(a)
b2 = sorted([i for i in b if i > maxa],reverse=True)
for k in b2:
    if h > 0:
        ans += 1
        h -= k
if h > 0: ans += ceil(h/maxa)
print(ans)