#include<bits/stdc++.h>

typedef unsigned int uint;
typedef long long ll;
typedef unsigned long long ull;
typedef double lf;
typedef long double llf;
typedef std::pair<int,int> pii;

#define xx first
#define yy second

template<typename T> inline T max(T a,T b){return a>b?a:b;}
template<typename T> inline T min(T a,T b){return a<b?a:b;}
template<typename T> inline T abs(T a){return a>0?a:-a;}
template<typename T> inline bool repr(T &a,T b){return a<b?a=b,1:0;}
template<typename T> inline bool repl(T &a,T b){return a>b?a=b,1:0;}
template<typename T> inline T gcd(T a,T b){T t;if(a<b){while(a){t=a;a=b%a;b=t;}return b;}else{while(b){t=b;b=a%b;a=t;}return a;}}
template<typename T> inline T sqr(T x){return x*x;}
#define mp(a,b) std::make_pair(a,b)
#define pb push_back
#define I __attribute__((always_inline))inline
#define mset(a,b) memset(a,b,sizeof(a))
#define mcpy(a,b) memcpy(a,b,sizeof(a))

#define fo0(i,n) for(int i=0,i##end=n;i<i##end;i++)
#define fo1(i,n) for(int i=1,i##end=n;i<=i##end;i++)
#define fo(i,a,b) for(int i=a,i##end=b;i<=i##end;i++)
#define fd0(i,n) for(int i=(n)-1;~i;i--)
#define fd1(i,n) for(int i=n;i;i--)
#define fd(i,a,b) for(int i=a,i##end=b;i>=i##end;i--)
#define foe(i,x)for(__typeof((x).end())i=(x).begin();i!=(x).end();++i)
#define fre(i,x)for(__typeof((x).rend())i=(x).rbegin();i!=(x).rend();++i)

struct Cg{I char operator()(){return getchar();}};
struct Cp{I void operator()(char x){putchar(x);}};
#define OP operator
#define RT return *this;
#define UC unsigned char
#define RX x=0;UC t=P();while((t<'0'||t>'9')&&t!='-')t=P();bool f=0;\
if(t=='-')t=P(),f=1;x=t-'0';for(t=P();t>='0'&&t<='9';t=P())x=x*10+t-'0'
#define RL if(t=='.'){lf u=0.1;for(t=P();t>='0'&&t<='9';t=P(),u*=0.1)x+=u*(t-'0');}if(f)x=-x
#define RU x=0;UC t=P();while(t<'0'||t>'9')t=P();x=t-'0';for(t=P();t>='0'&&t<='9';t=P())x=x*10+t-'0'
#define TR *this,x;return x;
I bool IS(char x){return x==10||x==13||x==' ';}template<typename T>struct Fr{T P;I Fr&OP,(int&x)
{RX;if(f)x=-x;RT}I OP int(){int x;TR}I Fr&OP,(ll &x){RX;if(f)x=-x;RT}I OP ll(){ll x;TR}I Fr&OP,(char&x)
{for(x=P();IS(x);x=P());RT}I OP char(){char x;TR}I Fr&OP,(char*x){char t=P();for(;IS(t);t=P());if(~t){for(;!IS
(t)&&~t;t=P())*x++=t;}*x++=0;RT}I Fr&OP,(lf&x){RX;RL;RT}I OP lf(){lf x;TR}I Fr&OP,(llf&x){RX;RL;RT}I OP llf()
{llf x;TR}I Fr&OP,(uint&x){RU;RT}I OP uint(){uint x;TR}I Fr&OP,(ull&x){RU;RT}I OP ull(){ull x;TR}};Fr<Cg>in;
#define WI(S) if(x){if(x<0)P('-'),x=-x;UC s[S],c=0;while(x)s[c++]=x%10+'0',x/=10;while(c--)P(s[c]);}else P('0')
#define WL if(y){lf t=0.5;for(int i=y;i--;)t*=0.1;if(x>=0)x+=t;else x-=t,P('-');*this,(ll)(abs(x));P('.');if(x<0)\
x=-x;while(y--){x*=10;x-=floor(x*0.1)*10;P(((int)x)%10+'0');}}else if(x>=0)*this,(ll)(x+0.5);else *this,(ll)(x-0.5);
#define WU(S) if(x){UC s[S],c=0;while(x)s[c++]=x%10+'0',x/=10;while(c--)P(s[c]);}else P('0')
template<typename T>struct Fw{T P;I Fw&OP,(int x){WI(10);RT}I Fw&OP()(int x){WI(10);RT}I Fw&OP,(uint x){WU(10);RT}
I Fw&OP()(uint x){WU(10);RT}I Fw&OP,(ll x){WI(19);RT}I Fw&OP()(ll x){WI(38);RT}I Fw&OP,(ull x){WU(20);RT}I Fw&OP()
(ull x){WU(20);RT}I Fw&OP,(char x){P(x);RT}I Fw&OP()(char x){P(x);RT}I Fw&OP,(const char*x){while(*x)P(*x++);RT}
I Fw&OP()(const char*x){while(*x)P(*x++);RT}I Fw&OP()(lf x,int y){WL;RT}I Fw&OP()(llf x,int y){WL;RT}};Fw<Cp>out;

namespace flow
{
	const int N=2300,M=33000,Nf=4095;

	struct edge
	{
		int to,w,ne,v;
	}e[M*2+2];
	
	int p[N+1],em=2,q[N<<1],qe,fa[N+1],dis[N+1];
	bool vis[N+1];
	
	int add(int a,int b,int w,int v)
	{
		//out,"add:",a,' ',b,' ',w,' ',v,'\n';
		e[em].to=b,e[em].w=w,e[em].v=v,e[em].ne=p[a],p[a]=em++;
		e[em].to=a,e[em].w=0,e[em].v=-v,e[em].ne=p[b],p[b]=em++;
		return em-1;
	}
	
	int fafa(int s,int t,int &cost)
	{
		cost=0;
		int flow=0;
		while(1)
		{
			memset(dis,0x3f,sizeof(dis));
			memset(fa,0x3f,sizeof(fa));
			dis[s]=0; 
			vis[s]=1;
			q[0]=s,qe=1;
			for(int i=0;i^qe;i++)
			{
				int k=q[i&Nf];
				for(int j=p[k];j;j=e[j].ne)
					if(e[j].w&&dis[e[j].to]>dis[k]+e[j].v)
					{
						dis[e[j].to]=dis[k]+e[j].v;
						fa[e[j].to]=j^1;
						if(!vis[e[j].to])q[(qe++)&Nf]=e[j].to,vis[e[j].to]=1;
					}
				vis[k]=0;
			}
			if(fa[t]==0x3f3f3f3f)break;
			int rfl=0x7fffffff;
			for(int i=t;i!=s;i=e[fa[i]].to)
				repl(rfl,e[fa[i]^1].w);
			cost+=dis[t]*rfl;
			flow+=rfl;
			for(int i=t;i!=s;i=e[fa[i]].to)
				e[fa[i]].w+=rfl,e[fa[i]^1].w-=rfl;
		}
		return flow;
	}
}

const int N=10,M=1<<N|5;

int n,d,ac,es,ed[M][N],ee[M],eu[M],ans[M*10];
char s[N+1];
bool req[M];

int&gw(int x){return flow::e[x].w;}

void dfs(int x)
{
	fo0(i,n)if(ed[x][i]&&gw(ed[x][i]))
	{
		ans[ac++]=i;
		gw(ed[x][i])--;
		return dfs(x|1<<i);
	}
	assert(gw(ee[x])--);
}

int main()
{
	in,n,d;
	fo0(i,d)
	{
		in,s;
		int t=0;
		fo0(j,n)t|=(s[j]-48)<<j;
		req[t]=1;
	}
	// 0 ~ 2^n-1 in, 2^n ~ 2^n*2-1 out
	// u=2^n*2, u=S, u+1=T, u+2=super-S, u+3=super-T
	int u=1<<n+1,m=1<<n;
	flow::add(u+1,u,m,0);
	es=flow::add(u,0,m,1);
	fo0(i,m)ee[i]=flow::add(i+m,u+1,1,0);
	fo0(i,m)
	{
		if(req[i])flow::add(i,u+3,1,0),eu[i]=flow::add(u+2,i+m,1,0);
		flow::add(i,i+m,m,0);
	}
	fo0(i,m)
	{
		fo0(j,n)if(~i>>j&1)
		{
			int k=i|1<<j;
			ed[i][j]=flow::add(i+m,k,m,1);
		}
	}
	int res;
	flow::fafa(u+2,u+3,res);
	out,res-1,'\n';
	//fo0(i,m)out,gw(eu[i]),' ';out,'\n';
	fo0(i,gw(es))
	{
		if(i!=0)ans[ac++]=-1;
		dfs(0);
	}
	assert(ac==res-1);
	fo0(i,ac)
	{
		if(ans[i]==-1)out,"R ";
		else out,ans[i],' ';
	}
	out,'\n';
}