import java.io.*;
import java.math.*;
import java.util.*;


class Main {
	static int[] vy = {1,0,-1,0};
	static int[] vx = {0,1,0,-1};
	static long mod = 1000000007;
	public static void main(String[] args) {	
		FastScanner sc = new FastScanner();
		//Scanner sc = new Scanner(System.in);
		PrintWriter out = new PrintWriter(System.out);
		int M = sc.nextInt();
		int N = sc.nextInt();
		char[][] map = new char[M][];
		for(int i = 0; i < M; i++) {
			map[i] = sc.next().toCharArray();
		}
		
		
		int sum = 0;
		boolean ok = true;
		while(ok) {
			ok = false;
			for(int i = 0; i < M; i++) {
				for(int j = 0; j < N; j++) {
					if(map[i][j] != '.') continue;
					int[] count = new int[26];
					for(int k = 0; k < 4; k++) {
						for(int l = 0; ; l++) {
							int tx = j + vx[k] * l;
							int ty = i + vy[k] * l;
							if(tx < 0 || ty < 0 || tx >= N || ty >= M) break;
							if(map[ty][tx] == '.') continue;
							count[map[ty][tx] - 'A']++;
							break;
						}
					}
					for(int kk = 0; kk < 26; kk++) {
						if(count[kk] == 2) {
							for(int k = 0; k < 4; k++) {
								for(int l = 0; ; l++) {
									int tx = j + vx[k] * l;
									int ty = i + vy[k] * l;
									if(tx < 0 || ty < 0 || tx >= N || ty >= M) break;
									if(map[ty][tx] == '.') continue;
									if(map[ty][tx] - 'A' != kk) break;
									map[ty][tx] = '.';
								} 
							}
							sum += 2;
							ok = true;
						}
					}
				}
			}
			
		}
		System.out.println(sum);
	}
	
	static class FastScanner {
	    private final InputStream in = System.in;
	    private final byte[] buffer = new byte[1024];
	    private int ptr = 0;
	    private int buflen = 0;
	    private boolean hasNextByte() {
	        if (ptr < buflen) {
	            return true;
	        }else{
	            ptr = 0;
	            try {
	                buflen = in.read(buffer);
	            } catch (IOException e) {
	                e.printStackTrace();
	            }
	            if (buflen <= 0) {
	                return false;
	            }
	        }
	        return true;
	    }
	    private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
	    private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
	    private void skipUnprintable() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;}
	    public boolean hasNext() { skipUnprintable(); return hasNextByte();}
	    public String next() {
	        if (!hasNext()) throw new NoSuchElementException();
	        StringBuilder sb = new StringBuilder();
	        int b = readByte();
	        while(isPrintableChar(b)) {
	            sb.appendCodePoint(b);
	            b = readByte();
	        }
	        return sb.toString();
	    }
	    public long nextLong() {
	        if (!hasNext()) throw new NoSuchElementException();
	        long n = 0;
	        boolean minus = false;
	        int b = readByte();
	        if (b == '-') {
	            minus = true;
	            b = readByte();
	        }
	        if (b < '0' || '9' < b) {
	            throw new NumberFormatException();
	        }
	        while(true){
	            if ('0' <= b && b <= '9') {
	                n *= 10;
	                n += b - '0';
	            }else if(b == -1 || !isPrintableChar(b)){
	                return minus ? -n : n;
	            }else{
	                throw new NumberFormatException();
	            }
	            b = readByte();
	        }
	    }
	    public int nextInt() {
	        if (!hasNext()) throw new NoSuchElementException();
	        int n = 0;
	        boolean minus = false;
	        int b = readByte();
	        if (b == '-') {
	            minus = true;
	            b = readByte();
	        }
	        if (b < '0' || '9' < b) {
	            throw new NumberFormatException();
	        }
	        while(true){
	            if ('0' <= b && b <= '9') {
	                n *= 10;
	                n += b - '0';
	            }else if(b == -1 || !isPrintableChar(b)){
	                return minus ? -n : n;
	            }else{
	                throw new NumberFormatException();
	            }
	            b = readByte();
	        }
	    }
	}
}

Measured memory_bytes: 59680