import math
N,H = map(int,input().split())
swing, thrower = 0,[]
for i in range(N):
    a,b = map(int,input().split())
    swing = max(a,swing)
    thrower.append(b)
ans = 0
thrower.append(0)
thrower.sort()
for i in range(N):
    if thrower[-1] < swing:
        break
    H -= thrower.pop(-1)
    ans += 1
    if H < 0:
        print(ans)
        exit()
ans += math.ceil(H/swing)
print(ans)
