5

package main

import (
    "bufio"
    "fmt"
    "os"
    "strconv"
    "strings"
)

func maxMushrooms(n int, forest [][]rune) int {
    if n == 0 {
        return 0
    }

    dp := make([][]int, n)
    for i := range dp {
        dp[i] = []int{-1, -1, -1}
    }

    countFirstBushes := 0
    for j := 0; j < 3; j++ {
        if forest[0][j] == 'C' {
            dp[0][j] = 1
        } else if forest[0][j] == 'W' {
            countFirstBushes++
        } else {
            dp[0][j] = 0
        }
    }
    if countFirstBushes == 3 {
        return 0
    }
    i := 1
    countImpossibleCells := 0
    for ; i < n; i++ {
        for j := 0; j < 3; j++ {
            if forest[i][j] == 'W' {
                countImpossibleCells++
                continue
            }
            for k := -1; k <= 1; k++ {
                if j+k >= 0 && j+k < 3 && dp[i-1][j+k] > dp[i][j] {
                    dp[i][j] = dp[i-1][j+k]
                }
            }
            if dp[i][j] == -1 {
                countImpossibleCells++
                continue
            }
            if forest[i][j] == 'C' {
                dp[i][j]++
            }
        }
        if countImpossibleCells == 3 {
            break
        }
        countImpossibleCells = 0
    }

    maxMushrooms := 0
    for j := 0; j < 3; j++ {
        if dp[i-1][j] > maxMushrooms {
            maxMushrooms = dp[i-1][j]
        }
    }

    return maxMushrooms
}

func main() {
    scanner := bufio.NewScanner(os.Stdin)
    buf := make([]byte, 1e4)
    scanner.Buffer(buf, 1e4)

    scanner.Scan()
    n, _ := strconv.Atoi(strings.Split(scanner.Text(), " ")[0])

    forest := make([][]rune, n)
    for i := range forest {
        scanner.Scan()
        fields := strings.Fields(scanner.Text())
        forest[i] = make([]rune, 3)
        for j := 0; j < len(fields[0]); j++ {
            forest[i][j] = []rune(fields[0])[j]
        }
    }

    result := maxMushrooms(n, forest)
    fmt.Println(result)
}