// LUOGU_RID: 98471925
#include<bits/stdc++.h>
using namespace std;
const int MAXN=1001;
const int dx[]={-1,-1,-1,0,0,1,1,1};
const int dy[]={-1,0,1,-1,1,-1,0,1};
struct node {
	int x,y,c;
};
int a[MAXN][MAXN];
inline bool valid(int x,int y) {
	int col=max(max(a[x][y],a[x+1][y+1]),max(a[x][y+1],a[x+1][y]));
	if(!col) return false;
	return (a[x][y]==col||a[x][y]==0)&&(a[x+1][y+1]==col||a[x+1][y+1]==0)&&
		   (a[x+1][y]==col||a[x+1][y]==0)&&(a[x][y+1]==col||a[x][y+1]==0);
}
inline int color(int x,int y) {
	return max(max(a[x][y],a[x+1][y+1]),max(a[x][y+1],a[x+1][y]));
}
signed main() {
	int n,m;
	scanf("%d%d",&n,&m);
	vector <node> op; queue <node> q;
	for(int i=1;i<=n;++i) {
		for(int j=1;j<=m;++j) {
			scanf("%d",&a[i][j]);
		}
	}
	for(int i=1;i<n;++i) {
		for(int j=1;j<m;++j) {
			if(valid(i,j)) q.push((node){i,j,0});
		}
	}
	while(!q.empty()) {
		int x=q.front().x,y=q.front().y; q.pop();
		if(color(x,y)==0) continue;
		op.push_back((node){x,y,color(x,y)});
		a[x][y]=a[x+1][y]=a[x][y+1]=a[x+1][y+1]=0;
		for(int k=0;k<8;++k) {
			int tx=x+dx[k],ty=y+dy[k];
			if(tx<1||ty<1||tx>=n||ty>=m) continue;
			if(valid(tx,ty)) q.push((node){tx,ty,0});
		}
	}
	for(int i=1;i<=n;++i) {
		for(int j=1;j<=m;++j) {
			if(a[i][j]!=0) {
				puts("-1");
				return 0;
			}
		}
	}
	printf("%d\n",(int)op.size());
	reverse(op.begin(),op.end());
	for(auto u:op) printf("%d %d %d\n",u.x,u.y,u.c);
	return 0;
}