n, h = map(int, input().split())
a = [0]*n
b = [0]*n
maxa = 0
for i in range(n):
    a[i], b[i] = map(int, input().split())
    maxa = max(maxa, a[i]) 
b.sort()
bsum = sum(b)
count = n

if bsum >= h:
    i = 0
    while bsum - b[i] > h:
        bsum -= b[i]
        i += 1
        count -= 1
else:
    if (h - bsum) % maxa == 0:
        count += (h - bsum) // maxa
    else:
        count += (h - bsum + 1)//maxa



print(count)