J. Stepan's Series

Codeforces

IDCF774J

Time2000ms

Memory256MB

Difficulty—

Well, the series which Stepan watched for a very long time, ended. In total, the series had _n_ episodes. For each of them, Stepan remembers either that he definitely has watched it, or that he definitely hasn't watched it, or he is unsure, has he watched this episode or not. Stepan's dissatisfaction is the **maximum** number of consecutive series that Stepan did not watch. Your task is to determine according to Stepan's memories if his dissatisfaction could be exactly equal to _k_. ## Input The first line contains two integers _n_ and _k_ (1 ≤ _n_ ≤ 100, 0 ≤ _k_ ≤ _n_) — the number of episodes in the series and the dissatisfaction which should be checked. The second line contains the sequence which consists of _n_ symbols "_Y_", "_N_" and "_?_". If the _i_\-th symbol equals "_Y_", Stepan remembers that he has watched the episode number _i_. If the _i_\-th symbol equals "_N_", Stepan remembers that he hasn't watched the epizode number _i_. If the _i_\-th symbol equals "_?_", Stepan doesn't exactly remember if he has watched the episode number _i_ or not. ## Output If Stepan's dissatisfaction can be exactly equal to _k_, then print "_YES_" (without qoutes). Otherwise print "_NO_" (without qoutes). [samples] ## Note In the first test Stepan remembers about all the episodes whether he has watched them or not. His dissatisfaction is 2, because he hasn't watch two episodes in a row — the episode number 3 and the episode number 4. The answer is "_YES_", because _k_ = 2. In the second test _k_ = 1, Stepan's dissatisfaction is greater than or equal to 2 (because he remembers that he hasn't watch at least two episodes in a row — number 5 and number 6), even if he has watched the episodes from the first to the fourth, inclusive.

Samples

Input #1

5 2
NYNNY

Output #1

YES

Input #2

6 1
????NN

Output #2

NO

API Response (JSON)

{
  "problem": {
    "name": "J. Stepan's Series",
    "description": {
      "content": "Well, the series which Stepan watched for a very long time, ended. In total, the series had _n_ episodes. For each of them, Stepan remembers either that he definitely has watched it, or that he defini",
      "description_type": "Markdown"
    },
    "platform": "Codeforces",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "CF774J"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "Well, the series which Stepan watched for a very long time, ended. In total, the series had _n_ episodes. For each of them, Stepan remembers either that he definitely has watched it, or that he defini...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments