#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
typedef long long int ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<vvvl> vvvvl;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;
typedef vector<vvvb> vvvvb;
typedef pair<ll,ll> pl;
typedef pair<ll,pl> ppl;
typedef pair<ll,ppl> pppl;
typedef pair<ll,pppl> pppppl;
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(a) begin(a),end(a)
#define sz(a) (int)(a).size()
#define F first
#define S second
#define bs(A,x) binary_search(all(A),x)
#define lb(A,x) (ll)(lower_bound(all(A),x)-A.begin())
#define ub(A,x) (ll)(upper_bound(all(A),x)-A.begin())
#define cou(A,x) (ll)(upper_bound(all(A),x)-lower_bound(all(A),x))
template<typename T>using min_priority_queue=priority_queue<T,vector<T>,greater<T>>;
template<class T>bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T&a,T b){if(b<a){a=b;return 1;}return 0;}
//*
using mint=modint998244353;
const ll mod=998244353;
//*/
/*
using mint=modint1000000007;
const ll mod=1000000007;
//*/
//using mint=modint;
//*
typedef vector<mint> vm;
typedef vector<vm> vvm;
typedef vector<vvm> vvvm;
typedef vector<vvvm> vvvvm;
ostream&operator<<(ostream&os,mint a){os<<a.val();return os;}
istream&operator>>(istream&is,mint&a){int x;is>>x;a=mint(x);return is;}
//*/
template<typename T1,typename T2>ostream&operator<<(ostream&os,pair<T1,T2>p){os<<p.F<<" "<<p.S;return os;}
template<typename T1,typename T2>istream&operator>>(istream&is,pair<T1,T2>&p){is>>p.F>>p.S;return is;}
template<typename T>ostream&operator<<(ostream&os,vector<T>v){rep(i,0,sz(v))os<<v[i]<<(i+1!=sz(v)?" ":"");return os;}
template<typename T>istream&operator>>(istream&is,vector<T>&v){for(T&in:v)is>>in;return is;}
int main(){
  cin.tie(0)->sync_with_stdio(0);
  cin.exceptions(cin.failbit);
  ll X,Y,Z;cin>>X>>Y>>Z;
  swap(X,Z);
  vector<vector<string>>S(X,vector<string>(Y)),T(X,vector<string>(Y));cin>>S>>T;
  vm A(8*X*Y*Z),B(8*X*Y*Z);
  rep(i,0,X)rep(j,0,Y)rep(k,0,Z){
  	ll t=4*i*Y*Z+2*j*Z+k;
  	A[t]=A[t+Z]=A[t+2*Y*Z]=A[t+2*Y*Z+Z]=A[t+4*X*Y*Z]=A[t+4*X*Y*Z+Z]=A[t+4*X*Y*Z+2*Y*Z]=A[t+4*X*Y*Z+2*Y*Z+Z]=(S[i][j][k]=='.'?0:S[i][j][k]=='B'?1:2);
  	B[t]=(T[i][j][k]=='.'?0:T[i][j][k]=='B'?1:2);
  }
  vm C(8*X*Y*Z),D(8*X*Y*Z),E(8*X*Y*Z),F(8*X*Y*Z);
  rep(i,0,8*X*Y*Z)C[i]=A[i]*A[i],D[i]=A[i]*A[i]*A[i];
  rep(i,0,8*X*Y*Z)E[i]=B[i]*B[i],F[i]=B[i]*B[i]*B[i];
  reverse(all(A));reverse(all(C));reverse(all(D));
  auto P=convolution(A,F);
  auto Q=convolution(C,E);
  auto R=convolution(D,B);
  rep(i,0,sz(P))P[i]=P[i]-2*Q[i]+R[i];
  ll ans=1e18;
  rep(i,0,X)rep(j,0,Y)rep(k,0,Z)chmin(ans,(ll)P[8*X*Y*Z-1-(4*i*Y*Z+2*Z*j+k)].val());
  cout<<ans/2<<endl;
  return 0;
}