#include <iostream>
#include <cstring>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <time.h>
#include <string>
#include <map>
#include <stack>
#include <vector>
#include <set>
#include <queue>
#define inf 0x3f3f3f3f
#define mod 1000000007
typedef long long ll;
using namespace std;
const int N=55;
int n,dp[N],len;
string w[N];
int vis[N][N];
int m,t;
int d[4][2]={1,0,0,1,-1,0,0,-1};
set<int>p;
int minn=inf;
struct man {int x,y;int st;
};
queue<man>q;
void bfs(int aa,int bb,char ch) {
man s;s.x=aa;s.y=bb;s.st=ch;q.push(s);
vis[aa][bb]=1;
while(!q.empty())
{man t=q.front();q.pop();for(int i=0;i<4;i++){int xx=t.x+d[i][0],yy=t.y+d[i][1];if(xx>=0&&xx<n&&yy>=0&&yy<m&&w[xx][yy]>=t.st&&vis[xx][yy]==0){man k;k.x=xx;k.y=yy;k.st=w[xx][yy];vis[xx][yy]=1;q.push(k);}}
}
}int main() {cin>>t;while(t--) {int ans=0;while(!q.empty())q.pop();memset(vis,0,sizeof(vis));cin>>n>>m;for(int i=0; i<n; i++)cin>>w[i];for(char ch='a'; ch<='z'; ch++) {for(int i=0; i<n; i++) {for(int j=0; j<m; j++) {if(w[i][j]==ch&&vis[i][j]==0){ans++;bfs(i,j,ch);}}}}cout<<ans<<endl;}return 0;
}

#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
#include<cstring>
#include<vector>
#include <climits>
#include <map>
using namespace std;
const int MAXN = 53;
int N, M;
char maze[MAXN][MAXN];
char s[MAXN][MAXN];
int xi[] = {0, 0, -1, 1};
int yi[] = {1, -1, 0, 0};
void dfs(int x, int y) {s[x][y] = 1;for(int i = 0; i < 4; i++) {int nx = x + xi[i];int ny = y + yi[i];//printf("%d %d %c\n", nx, ny,maze[nx][ny]);if(nx>=0 && nx < N && ny >= 0 && ny < M && s[nx][ny] == 0 && maze[nx][ny] >= maze[x][y]) {dfs(nx, ny);}}
}
int main() {int t = 0;scanf("%d", &t);while(t--) {scanf("%d%d", &N, &M);for(int i = 0; i < N; i++) {scanf("%s", maze[i]);}memset(s, 0, sizeof(s));int cnt = 0;for(char c = 'a'; c <= 'z'; c++) {for(int i = 0; i < N; i++) {for(int j = 0; j < M; j++) {if(s[i][j] == 0 && maze[i][j] == c){dfs(i, j);cnt++;}}}}printf("%d\n", cnt);}return 0;
}