1 /* 2    构造：从大到小构造，每一次都把最后不是9的变为9，p - p MOD 10^k - 1，直到小于最小值。 3         另外，最多len-1次循环 4 */ 5 #include 
     
       6 #include 
      
        7 #include 
       
         8 #include 
        
          9 using namespace std;10 11 typedef long long ll;12 const int MAXN = 1e3 + 10;13 const int INF = 0x3f3f3f3f;14 15 int get_len(ll x)   {16     int ret = 0;17     while (x)   {18         x /= 10;    ret++;19     }20     return ret;21 }22 23 int get_nine(ll x)  {24     int ret = 0;25     while (x)   {26         ll y = x % 10;  x /= 10;27         if (y != 9) break;28         ret++;29     }30     return ret;31 }32 33 int main(void)  {       //Codeforces Round #135 (Div. 2) B. Special Offer! Super Price 999 Bourles!34     //freopen ("C.in", "r", stdin);35     36     ll p, d;37     while (scanf ("%I64d%I64d", &p, &d) == 2)   {38         int len = get_len (p);  ll now = p;39         int mx = get_nine (p);  ll ans = p;40         ll cut = 1;41         while (true)    {42             ll y = now / cut % 10;43             if (y != 9) {44                 now = now - cut * 10;    now = now / cut + cut - 1;45             }46             cut *= 10;47             if (now < p - d)    break;48             int cnt = get_nine (now);49             if (cnt > mx)   ans = now;50         }51 52         printf ("%I64d\n", ans);53     }54 55     return 0;56 }