#include <iostream>
#include <fstream>
#include <bitset>
#include <queue>
#define M 405
using namespace std;
fstream fin("ferma.in",ios::in),fout("ferma.out",ios::out);
int di[]={-1,0,1,0},dj[]={0,1,0,-1},n,m,t,who[M][M],cost[M*M],aux[M*M];
queue <pair<int,int> > v;
char color,s[M][M];

void citire(){
    cin>>t>>n>>m;
    for(int i=1;i<=n;i++) cin>>(s[i]+1);
}

int bfs(int i,int j,int ind)
{
    int total=1,k;
    who[i][j]=ind;
    v.push(make_pair(i,j));

    while(!v.empty())
    {
        i=v.front().first;
        j=v.front().second;
        for(k=0;k<4;k++)
        {
            if(s[i+di[k]][j+dj[k]]==s[i][j]&&0<i+di[k]&&i+di[k]<=n&&0<j+dj[k]&&j+dj[k]<=m)
            {
                if(who[i+di[k]][j+dj[k]]==0)
                {
                    who[i+di[k]][j+dj[k]]=ind;
                    total++;
                    v.push(make_pair(i+di[k],j+dj[k]));
                }
            }
        }
        v.pop();
    }
    return total;
}
void cmp(int x1,int y1,int x2,int y2)
{
    if(who[x1][y1]!=who[x2][y2]&& 0<x1&&x1<=n&& 0<x2&&x2<=n&& 0<y1&&y1<=m&& 0<y2&&y2<=m)
    {
        if(s[x1][y1]==s[x2][y2])
        {
            aux[who[x1][y1]]=max(aux[who[x1][y1]],cost[who[x1][y1]]+cost[who[x2][y2]]);
        }
    }
}
int main()
{
    int a,i,j,ind=1,maxim1=-99999,maxim2=-99999,xi,xj,k,r;
    citire();
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=m;j++)
        {
            if(who[i][j]==0)
            {
                cost[ind]=bfs(i,j,ind);
                maxim1=max(maxim1,cost[ind]);
                ind++;
            }
        }
    }
    if(t==2)
    {
        for(i=1;i<=n;i++)
        {
            for(j=1;j<=m;j++)
            {
                //prima
                //aux[who[i-1][j]]=-M;
                cmp(i-1,j,i,j+1);
                cmp(i-1,j,i+1,j);
                cmp(i-1,j,i,j-1);
                //a doua
                //aux[who[i][j+1]]=-M;
                cmp(i,j+1,i+1,j);
                cmp(i,j+1,i,j-1);
                //a treia
                //aux[who[i+1][j]]=-M;
                cmp(i+1,j,i,j-1);

                for(k=0;k<4;k++)
                {
                    if(who[i][j]!=who[i+di[k]][j+dj[k]]&&s[i][j]!=s[i+di[k]][j+dj[k]])
                    {
                        if(maxim2<aux[who[i+di[k]][j+dj[k]]])
                        {
                            maxim2=aux[who[i+di[k]][j+dj[k]]];
                            xi=i;
                            xj=j;
                            color=s[i+di[k]][j+dj[k]];
                        }
                    }
                }
            }
        }
        //cout<<xi<<" "<<xj<<"\n"<<color<<"\n";
        return 0;
    }
    cout<<maxim1<<"\n";
    return 0;
}