#include "cstdio"#include "cstring"int r,c;char map[55][55];int vis[55][55];int mark;int dx[4]={
   1,-1,0,0},dy[4]={
   0,0,1,-1};int judge(int x,int y){    if(x<0||x>=r||y<0||y>=c)        return 0;    return 1;}void dfs(int x,int y,int perX,int perY){    if(!judge(x,y))        return;    vis[x][y]=1;    for(int i=0;i<4;i++)    {        int xx=x+dx[i];        int yy=y+dy[i];        if(map[xx][yy]==map[x][y]&&judge(xx,yy)&&(xx!=perX||yy!=perY))        {            if(vis[xx][yy])            {                mark=1;                return;            }            dfs(xx,yy,x,y);        }    }    return;}int main(){    while(scanf("%d%d",&r,&c)!=EOF)    {        memset(vis,0,sizeof(vis));        for(int i=0;i