#include<bits/stdc++.h>
#define MOD 1000000007
#define EPS 1e-15
#define ll long long
#define ld long double
#define pb push_back
#define mp make_pair
#define endl '\n'
#define foreach(it,x) for(__typeof__((x).begin()) it = (x).begin(); it != (x).end(); ++it)
const ld PI=3.141592653589793238L;
const ll N=100005;
using namespace std;

ll n;
ll r[1000],c[1000];
ll C[1000][1000];

int main(){
   ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
   // <<>>

   cin>>n;

   ll t[n][n];
   char ch;
   for(int i=0;i<n;++i) for(int j=0;j<n;++j) cin>>ch,t[i][j]=(ch=='B');

   for(int i=0;i<n;++i) for(int j=0;j<n;++j) if(!t[i][j]) ++r[i],++c[j],++C[i][j];

   vector<pair<ll,ll> >v1,v2;
   for(int i=0;i<n;++i) for(int j=0;j<n;++j){
      C[i][j]+=r[i]+c[j];
      if(C[i][j]&1) v1.pb(mp(i,j));
      else v2.pb(mp(i,j));
   }

   if(v2.size()<v1.size()) swap(v1,v2);

   cout<<v1.size()<<endl;
   for(int i=0;i<v1.size();++i) cout<<v1[i].first+1<<' '<<v1[i].second+1<<endl;

   return 0;
}