```go
package main

import (
	"bufio"
	"fmt"
	"os"
	"sort"
)

type Seat struct {
	r, c, cost int
}

func main() {
	reader := bufio.NewReader(os.Stdin)
	writer := bufio.NewWriter(os.Stdout)
	defer writer.Flush()

	var n, k int
	fmt.Fscan(reader, &n, &k)

	grid := make([][]byte, n)
	var candidates []Seat

	for i := 0; i < n; i++ {
		var s string
		fmt.Fscan(reader, &s)
		grid[i] = []byte(s)
		for j, char := range grid[i] {
			if char == '.' {
				cost := 0
				if j > 0 && grid[i][j-1] == 'S' {
					cost++
				}
				if j < len(grid[i])-1 && grid[i][j+1] == 'S' {
					cost++
				}
				candidates = append(candidates, Seat{i, j, cost})
			}
		}
	}

	sort.Slice(candidates, func(i, j int) bool {
		return candidates[i].cost < candidates[j].cost
	})

	for i := 0; i < k; i++ {
		seat := candidates[i]
		grid[seat.r][seat.c] = 'x'
	}

	totalNeighbors := 0
	for i := 0; i < n; i++ {
		for j, char := range grid[i] {
			if char == 'S' {
				if j > 0 {
					left := grid[i][j-1]
					if left == 'S' || left == 'P' || left == 'x' {
						totalNeighbors++
					}
				}
				if j < len(grid[i])-1 {
					right := grid[i][j+1]
					if right == 'S' || right == 'P' || right == 'x' {
						totalNeighbors++
					}
				}
			}
		}
	}

	fmt.Fprintln(writer, totalNeighbors)
	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, string(grid[i]))
	}
}
```