import math
N, H = map(int, input().split())
sword =[list(map(int, input().split())) for _ in range(N)]
def f1(l):
    a, b = l
    return a
def f2(l):
    a, b = l
    return b
sword.sort(key = f1)
amax, b1 = sword[-1]
sword.sort(key = f2)
dam = 0
ans = 0
while True:
    a, b = sword.pop()
    if a == amax:
        break
    else:
        dam += b
        ans += 1 
        if dam >= H:
            break
if dam < H:
    ans += max(math.ceil((H-dam-b1)/amax), 0) + 1
print(ans)