#include <cstdio>
#include <cmath>
#include <cstring>
#include <cstdlib>
#include <climits>
#include <ctime>
#include <queue>
#include <stack>
#include <algorithm>
#include <list>
#include <vector>
#include <set>
#include <map>
#include <iostream>
#include <deque>
#include <complex>
#include <string>
#include <iomanip>
#include <sstream>
#include <bitset>
#include <valarray>
#include <iterator>
using namespace std;
typedef long long int ll;
typedef unsigned int uint;
typedef unsigned char uchar;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef vector<int> vi;

#define REP(i,x) for(int i=0;i<(int)(x);i++)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();i++)
#define RREP(i,x) for(int i=((int)(x)-1);i>=0;i--)
#define RFOR(i,c) for(__typeof((c).rbegin())i=(c).rbegin();i!=(c).rend();i++)
#define ALL(container) container.begin(), container.end()
#define RALL(container) container.rbegin(), container.rend()
#define SZ(container) ((int)container.size())
#define mp(a,b) make_pair(a, b)
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
#define X first
#define Y second

template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }
template<class T> ostream& operator<<(ostream &os, const vector<T> &t) {
os<<"["; FOR(it,t) {if(it!=t.begin()) os<<","; os<<*it;} os<<"]"; return os;
}
template<class T> ostream& operator<<(ostream &os, const set<T> &t) {
os<<"{"; FOR(it,t) {if(it!=t.begin()) os<<","; os<<*it;} os<<"}"; return os;
}
template<class S, class T> ostream& operator<<(ostream &os, const pair<S,T> &t) { return os<<"("<<t.first<<","<<t.second<<")";}

const int INF = 1<<28;
const double EPS = 1e-8;
const int MOD = 1000000007;


int N, M;

string m[501];
vector<pii> place[26];
vector<int> stock[26];
main(){
	cin >> M >> N;
	REP(i, M){
		cin >> m[i];
		REP(j, N){
			if(m[i][j] != '.') place[m[i][j]-'A'].emplace_back(j, i);
		}
	}
	REP(i, 26){
		if(place[i].empty()) continue;
		pii a = place[i][0];
		pii b = place[i][1];
		if(a > b) swap(a, b);
		if(a.X == b.X){
			if(a.Y+1 == b.Y) continue;
			int st = 0;
			for(int y=a.Y+1;y<b.Y;y++) if(m[y][a.X] != '.') st |= 1 << (m[y][a.X]-'A');
			stock[i].push_back(st);
		}else if(a.Y == b.Y){
			if(a.X+1 == b.X) continue;
			int st = 0;
			for(int x=a.X+1;x<b.X;x++) if(m[a.Y][x] != '.') st |= 1 << (m[a.Y][x]-'A');
			stock[i].push_back(st);
		}else{
			int st = 0;
			for(int x=a.X;x<=b.X;x++) if(m[a.Y][x] != '.' && m[a.Y][x] != 'A'+i) st |= 1 << (m[a.Y][x]-'A');
			for(int y=min(a.Y, b.Y);y<=max(a.Y, b.Y);y++) if(m[y][b.X] != '.' && m[y][b.X] != 'A'+i) st |= 1 << (m[y][b.X]-'A');
			stock[i].push_back(st);
			
			st = 0;
			for(int x=a.X;x<=b.X;x++) if(m[b.Y][x] != '.' && m[b.Y][x] != 'A'+i) st |= 1 << (m[b.Y][x]-'A');
			for(int y=min(a.Y, b.Y);y<=max(a.Y, b.Y);y++) if(m[y][a.X] != '.' && m[y][a.X] != 'A'+i) st |= 1 << (m[y][a.X]-'A');
			stock[i].push_back(st);
		}
	}
	int rest = (1<<26) -1;
	int ans = 0;
	REP(k, 26)REP(i, 26){
		REP(j, stock[i].size()){
			if((rest & stock[i][j]) == 0){
				ans += 2;
				rest ^= 1<<i;
				stock[i].clear();
				break;
			}
		}
	}
	cout << ans << endl;
	return 0;
}

Measured memory_bytes: 1492