// luogu-judger-enable-o2
#include<bits/stdc++.h>
#define il inline
#define reg register int
#define numb (ch^'0')
using namespace std;
typedef long long ll;
il void rd(int &x){char ch;bool fl=false;while(!isdigit(ch=getchar()))(ch=='-')&&(fl=true);for(x=numb;isdigit(ch=getchar());x=x*10+numb);(fl==true)&&(x=-x);
}
namespace Miracle{
const int N=100+5;
ll a[N][N];
int co[N*N];
int in[N*N];
int n,m;
struct node{int nxt,to;
}e[8*N*N];
int hd[N*N],cnt;
int num(int x,int y){return (x-1)*m+y;
}
void add(int x,int y){
//    cout<<" ahahhaa "<<endl;e[++cnt].nxt=hd[x];e[cnt].to=y;hd[x]=cnt;
}
int to[N*N];
int vis[N*N];
bool dfs(int x,int id){
//    cout<<" x "<<x<<" id "<<id<<endl;for(reg i=hd[x];i;i=e[i].nxt){int y=e[i].to;//    cout<<" yy "<<y<<" vis "<<vis[y]<<endl;if(vis[y]==id) continue;vis[y]=id;if(!to[y]||dfs(to[y],id)){to[y]=x;in[x]=1;to[x]=y;in[y]=1;return true;}}return false;
}
bool fin(int x,int id,int pos){if(vis[x]==id) return false;vis[x]=id;if(pos==0){if(!to[x]) return true;return fin(to[x],id,pos^1);}for(reg i=hd[x];i;i=e[i].nxt){int y=e[i].to;if(y!=to[x]){if(fin(y,id,pos^1)) return true;}}return false;
}
ll p[10]={2,3,7,61,24251};
ll add(ll x,ll y,ll p){return x+y>=p?x+y-p:x+y;
}
ll qk(ll x,ll y,ll p){ll ret=0;while(y){if(y&1) ret=add(ret,x,p);x=add(x,x,p);y>>=1;}return ret;
}
ll qm(ll x,ll y,ll p){ll ret=1;while(y){if(y&1) ret=qk(ret,x,p);x=qk(x,x,p);y>>=1;}return ret;
}
bool che(ll x,ll d){int s=0;ll lp=x-1;while(!(lp&1)){++s;lp>>=1;}ll now=qm(d,lp,x);if(now==1||now==x-1) return true;for(reg i=0;i<s;++i){ll tmp=qk(now,now,x);if(tmp==1&&(now!=1&&now!=x-1)) return false;now=tmp;}if(now!=1) return false;return true;
}
bool M_R(ll x){
//    cout<<" xx "<<x<<endl;if(x==0) return true;if(x==1) return true;if(x==46856248255981ll) return false; if(x==2||x==3||x==7||x==11||x==13||x==17||x==23||x==29||x==31||x==61||x==24251) return true;for(reg i=0;i<5;++i){if(x%p[i]==0) return false;if(!che(x,p[i])) return false;}
//    cout<<" ok "<<endl;return true;
}
int mem[N*N],nb;
int main(){
//    cout<<" M_R "<<M_R(1557403521852231)<<endl;
    rd(n);rd(m);
//    cout<<" 2333 "<<endl;for(reg i=1;i<=n;++i){for(reg j=1;j<=m;++j){scanf("%lld",&a[i][j]);co[num(i,j)]=(i+j)%2;}}//    return 0;for(reg i=1;i<=n;++i){for(reg j=1;j<=m;++j){if(a[i][j]==-1) continue;if(j!=m){if(a[i][j+1]!=-1){if(M_R(a[i][j]+a[i][j+1])==0){add(num(i,j),num(i,j+1));add(num(i,j+1),num(i,j));}}}if(i!=n){if(a[i+1][j]!=-1){if(M_R(a[i][j]+a[i+1][j])==0){add(num(i,j),num(i+1,j));add(num(i+1,j),num(i,j));//        cout<<num(i,j)<<" "<<num(i+1,j)<<endl;
                    }}}}}
//    cout<<" after build "<<endl;int tot=0;int le=0,ri=0;for(reg i=1;i<=n;++i){for(reg j=1;j<=m;++j){if(co[num(i,j)]==0&&a[i][j]!=-1){++le;tot+=dfs(num(i,j),num(i,j));}else if(a[i][j]!=-1) ++ri;}}
//    cout<<" le ri "<<le<<" "<<ri<<" tot "<<tot<<endl;if(le==ri&&tot==le){puts("0");return 0;}memset(vis,0,sizeof vis);for(reg i=1;i<=n;++i){for(reg j=1;j<=m;++j){if(a[i][j]!=-1){if(!in[num(i,j)]||fin(to[num(i,j)],num(i,j),1)){mem[++nb]=num(i,j);}}}}sort(mem+1,mem+nb+1);printf("%d\n",nb);for(reg i=1;i<=nb;++i){printf("%d %d\n",(mem[i]-1)/m+1,mem[i]-((mem[i]-1)/m)*m);}return 0;
}}
signed main(){
//    freopen("data3618.in","r",stdin);
//    freopen("data3618.out","w",stdout);
    Miracle::main();return 0;
}/*Author: *Miracle*Date: 2019/2/2 20:45:23
*/