#D65. Closed Rooms
Closed Rooms
Closed Rooms
Takahashi is locked within a building.
This building consists of H×W rooms, arranged in H rows and W columns. We will denote the room at the i-th row and j-th column as (i,j). The state of this room is represented by a character A_{i,j}. If A_{i,j}= #
, the room is locked and cannot be entered; if A_{i,j}= .
, the room is not locked and can be freely entered. Takahashi is currently at the room where A_{i,j}= S
, which can also be freely entered.
Each room in the 1-st row, 1-st column, H-th row or W-th column, has an exit. Each of the other rooms (i,j) is connected to four rooms: (i-1,j), (i+1,j), (i,j-1) and (i,j+1).
Takahashi will use his magic to get out of the building. In one cast, he can do the following:
- Move to an adjacent room at most K times, possibly zero. Here, locked rooms cannot be entered.
- Then, select and unlock at most K locked rooms, possibly zero. Those rooms will remain unlocked from then on.
His objective is to reach a room with an exit. Find the minimum necessary number of casts to do so.
It is guaranteed that Takahashi is initially at a room without an exit.
Constraints
- 3 ≤ H ≤ 800
- 3 ≤ W ≤ 800
- 1 ≤ K ≤ H×W
- Each A_{i,j} is
#
,.
orS
. - There uniquely exists (i,j) such that A_{i,j}=
S
, and it satisfies 2 ≤ i ≤ H-1 and 2 ≤ j ≤ W-1.
Input
Input is given from Standard Input in the following format:
H W K A_{1,1}A_{1,2}...A_{1,W} : A_{H,1}A_{H,2}...A_{H,W}
Output
Print the minimum necessary number of casts.
Examples
Input
3 3 3 #.# #S.
Output
1
Input
3 3 3 .# S.
Output
1
Input
3 3 3
S#
Output
2
Input
7 7 2
...## S### .#.## .###
Output
2
inputFormat
Input
Input is given from Standard Input in the following format:
H W K A_{1,1}A_{1,2}...A_{1,W} : A_{H,1}A_{H,2}...A_{H,W}
outputFormat
Output
Print the minimum necessary number of casts.
Examples
Input
3 3 3 #.# #S.
Output
1
Input
3 3 3 .# S.
Output
1
Input
3 3 3
S#
Output
2
Input
7 7 2
...## S### .#.## .###
Output
2
样例
3 3 3
#.#
#S.
###
1