#include "bits/stdc++.h"
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> veci;
typedef vector<ll> vecll;
typedef vector<string> vecs;
template<class T,class U> using Hash=unordered_map<T,U>;
 
#define REP(i, a, n) for(ll i = a; i < (ll)(n); i++)
#define RREP(i, a, n) for(ll i = n-1; i >= (ll)(a); i--)
#define rep(i, n) REP(i, 0, n)
#define rrep(i, n) RREP(i, 0, n)
#define MD 1000000007
#define _SPLIT " "
 
template<class T> T read(){T a;cin >> a;return a;}
template<class T> void read(T& a){cin >> a;}
template<class T,class ...Args> void read(T& a, Args&... args){cin >> a; read(args...);} 
template<class T> void rarr(T a, int n){for(int i = 0; i < n; i++) {cin >> a[i];}}
template<class T> void write(T a){cout << setprecision(24) << a << endl;}
template<class T,class ...Args> void write(T a, Args... args){cout << setprecision(24) << a << _SPLIT; write(args...);}
template<class T> void warr(vector<T> a, const char* c = " "){cout << a[0];for(int i = 1; i < (int)a.size(); i++)cout << c << a[i];cout << endl;;}
template<class T> void warr(T a, int n, const char* c = " "){cout << a[0];for(int i = 1; i < n; i++)cout << c << a[i];cout << endl;}
template<class T> void warr(T begin, T end, const char* c = " "){cout << *begin;for(auto i = begin+1; i != end; i++)cout << c << *i;cout << endl;}
void split(string s, string delim, veci& result){result.clear();string::size_type pos = 0;while(pos != string::npos){string::size_type p = s.find(delim, pos);if(p == string::npos){result.push_back(atoi(s.substr(pos).data()));break;}else {result.push_back(atoi(s.substr(pos, p - pos).data()));}pos = p + delim.size();}}
void split(string s, string delim, vecs& result){result.clear();string::size_type pos = 0;while(pos != string::npos){string::size_type p = s.find(delim, pos);if(p == string::npos){result.push_back(s.substr(pos));break;}else {result.push_back(s.substr(pos, p - pos));}pos = p + delim.size();}}
ll gcd(ll a, ll b){while(true){ll k = a % b;if(k == 0)return b;a = b;b = k;}}
ll comb(ll n, ll m){ll p=1;m=min(m,n-m);for(ll i=1;i<=m;i++){p*=n-i+1;p/=i;}return p;}

int h,w;
int dx[]={1,1,0,-1,-1,-1,1,0};
int dy[]={0,1,1,1,0,-1,-1,-1};

ll sw(ll n,int x,int y){
    int z=x+y*w;
    n^=1LL<<z;
    return n;
}
ll suround(ll n,int x,int y){
    n=sw(n,x,y);
    rep(i,8){
        int tx=x+dx[i];
        int ty=y+dy[i];
        if(tx>=0&&ty>=0&&tx<w&&ty<h)
            n=sw(n,tx,ty);
    }
    return n;
}

struct Info{
    ll val;
    int ct;
};

int main(void)
{
    ll n=0;
    read(h,w);
    rep(i,h*w){
        ll k;
        read(k);
        n|=k<<i;
    }
    queue<Info> st;
    unordered_set<ll> us;
    st.push({n,0});
    int res=-1;
    while(!st.empty()){
        Info pf=st.front();
        st.pop();
        if(pf.val==0){
            res=pf.ct;
            break;
        }
        rep(i,h)rep(j,w){
            int v=suround(pf.val,j,i);
            if(us.count(v)>0)continue;
            st.push({v,pf.ct+1});
            us.insert(v);
        }
    }
    if(res>=0)write(res);
    else write("Impossible");
    return 0;
}