#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
int tA = 0, tC = 0, tB = 0, tK1 = 0, tK2 = 0, tK3 = 0, tK4 = 0;

void K4(char ch){
    tC = tK4 + 4;
}
void K3(char ch){
    if (ch == 'B'){
        tB = tK3 + 2;
    }
    else{
        tC = tK3 + 4;
    }
}
void K2(char ch){
    tB = tK2 + 2;
}
void K1(char ch){
    if (ch == 'B'){
        if (tK3 <= tK2){
            tK3 = tK1 + 4;
            K3(ch);
        }
        else{
            tK2 = tK1 + 6;
            K2(ch);
        }
    }
    else{
        if (tK3 <= tK4){
            tK3 = tK1 + 8;
            K3(ch);
        }
        else {
            tK4 = tK1 + 12;
            K4(ch);
        }
    }
}
void A(char ch){
    if (ch == 'B'){
        tK1 += 1;
    }
    else tK1 += 2;
    K1(ch);
}
int main(){
    for (int i = 0; i < 16; ++i){
        char ch;
        cin >> ch;
        A(ch);
    }
    cout << max(tB, tC);
    return 0;
}