n, h = map(int, raw_input().split())
throw = []
hit = []
for i in range(0, n): 
    ai, bi = map(int, raw_input().split())
    throw += [bi]
    hit += [ai]
throw.sort(reverse = True)
hit.sort(reverse = True)

ans = 0 
hth = 0 

for i in range(0, n): 
    if(throw[i] < hit[0]):
        break
    if (hth >= h): 
        break
    ans += 1
    hth += throw[i]
if (h - hth > 0): 
    ans += (h - hth + hit[0] - 1) // hit[0]
print ans 