#pragma GCC target ("avx,avx2")
#pragma GCC optimize ("Ofast")
#include <algorithm>
#include <iostream>
#include <stdlib.h>
#include <iomanip>
#include <sstream>
#include <stdio.h>
#include <string>
#include <vector>
#include <cmath>
#include <map>

using namespace std;

int height, width;
vector < int > visited;
char floorPlan [ 1000000 ];
vector < int > startPoints;

bool dfs ( int i ) {

    for ( int j = 0; j < visited.size ( ); ++ j ) {

        if ( i ==  visited [ j ] )
            return true;

    }

    visited.push_back ( i );

    if ( i % 1000 == 0 || i % 1000 == width || i < width || ( height - 2 ) * 1000 < i )
        return false;

    if ( floorPlan [ i + 1 ] == '.' ) {
        if ( !dfs ( i + 1 ) )
        return false;
    }
    if ( floorPlan [ i - 1 ] == '.' ) {
        if ( !dfs ( i - 1 ) )
        return false;
    }
    if ( floorPlan [ i + 1000 ] == '.' ) {
        if ( !dfs ( i + 1000 ) )
        return false;
    }
    if ( floorPlan [ i - 1000 ] == '.' ) {
        if ( !dfs ( i - 1000 ) )
        return false;
    }

    return true;

}

int main ( ) {

    cin >> height >> width;

    for ( int i = 0; i < height; ++ i ) {

        for ( int j = 0; j < width; ++ j ) {

            cin >> floorPlan [ i * 1000 + j ];
            if ( floorPlan [ i * 1000 + j ] == 'X' )
                startPoints.push_back ( i * 1000 + j );

        }

    }

    for ( int i = 0; i < startPoints.size ( ); ++ i ) {
        if  ( !dfs ( startPoints [ i ] ) ) {
            cout << "Death to humans\n";
            return 0;
        }
    }

    cout << "We are safe\n";

    return 0;

}