#include<bits/stdc++.h>
using namespace std;
struct rec
{int nxt;int to;int w;
}e[2222222];
int head[300000],cnt;
int n,m;
char ch[600];
int st,ed;
bool Map[600][600];
int bs[600][600],u[600][600],d[600][600],l[600][600],r[600][600];
bool vis[300000];
int dis[300000];
queue<pair<int,int> > que;
priority_queue<pair<int,int>,vector<pair<int,int> >,greater<pair<int,int> > >q;
void add(int x,int y,int w)
{e[++cnt].nxt=head[x];e[cnt].to=y;e[cnt].w=w;head[x]=cnt;
}
void insert(int x,int y,int w)
{if(Map[x][y]&&!bs[x][y]){bs[x][y]=w;que.push(make_pair(x,y));}
}
void pre_bfs()
{while(!que.empty()){pair<int,int> flag=que.front();que.pop();insert(flag.first-1,flag.second,bs[flag.first][flag.second]+1);insert(flag.first,flag.second-1,bs[flag.first][flag.second]+1);insert(flag.first+1,flag.second,bs[flag.first][flag.second]+1);insert(flag.first,flag.second+1,bs[flag.first][flag.second]+1);}
}
void pre_work()
{for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)if(Map[i][j]){if(!Map[i][j-1])l[i][j]=(i-1)*m+j;else l[i][j]=l[i][j-1];if(!Map[i-1][j])u[i][j]=(i-1)*m+j;else u[i][j]=u[i-1][j];}for(int i=n;i;i--)for(int j=m;j;j--)if(Map[i][j]){if(!Map[i][j+1])r[i][j]=(i-1)*m+j;else r[i][j]=r[i][j+1];if(!Map[i+1][j])d[i][j]=(i-1)*m+j;else d[i][j]=d[i+1][j];}for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)if(Map[i][j]){if(Map[i][j+1]){add((i-1)*m+j,(i-1)*m+j+1,1);add((i-1)*m+j+1,(i-1)*m+j,1);}if(Map[i+1][j]){add((i-1)*m+j,i*m+j,1);add(i*m+j,(i-1)*m+j,1);}if(u[i][j]!=(i-1)*m+j)add((i-1)*m+j,u[i][j],bs[i][j]);if(d[i][j]!=(i-1)*m+j)add((i-1)*m+j,d[i][j],bs[i][j]);if(l[i][j]!=(i-1)*m+j)add((i-1)*m+j,l[i][j],bs[i][j]);if(r[i][j]!=(i-1)*m+j)add((i-1)*m+j,r[i][j],bs[i][j]);}
}
void Dij(int x)
{memset(dis,0x3f,sizeof(dis));q.push(make_pair(0,x));dis[x]=0;while(!q.empty()){int flag=q.top().second;q.pop();if(vis[flag])continue;vis[flag]=1;for(int i=head[flag];i;i=e[i].nxt)if(dis[e[i].to]>dis[flag]+e[i].w){dis[e[i].to]=dis[flag]+e[i].w;q.push(make_pair(dis[e[i].to],e[i].to));}}
}
int main()
{scanf("%d%d",&n,&m);for(int i=1;i<=n;i++){scanf("%s",ch+1);for(int j=1;j<=m;j++){if(ch[j]=='C')st=(i-1)*m+j;if(ch[j]=='F')ed=(i-1)*m+j;if(ch[j]=='#')que.push(make_pair(i,j));if(ch[j]=='C'||ch[j]=='F'||ch[j]=='.')Map[i][j]=1;}}pre_bfs();pre_work();Dij(st);printf("%d",dis[ed]);return 0;
}