#include<bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(n);i++)
using namespace std;
int main(){
	int H,W;
	cin>>H>>W;
	vector<string>S(H),T(H+2);
	T[0]=T[H+1]=string(W+2,'#');
	rep(i,H)cin>>S[i],T[i+1]='#'+S[i]+'#';
	vector<pair<int,int>>key;
	rep(i,H)rep(j,W)if(T[i+1][j+1]=='.')
		if((T[i][j+1]=='#'&&T[i+2][j+1]=='.') || (T[i+1][j]=='#'&&T[i+1][j+2]=='.'))
			key.emplace_back(i,j);

	cout<<key.size()<<endl;
	for(auto[i,j]:key)
	{
		string ansi("-"),ansj("-");
		int li=0,lj=0;
		if(T[i+2][j+1]=='.'){
			while(T[i+li+1][j+1]=='.')li++;
			ansi=string(li,'a');
		}
		if(T[i+1][j+2]=='.'){
			while(T[i+1][j+lj+1]=='.')li++;
			ansj=string(lj,'a');
		}
		cout<<ansi<<" "<<ansj<<endl;
	}
}