C++ :

#include<bits/stdc++.h>
#define R register
#define INF 0x3f3f3f3f
#define PI acos(-1.0)
#define N 26
#define MOD 2520
#define E 1e-12
using namespace std;
int r,c;
char a[N][N];
bool vis[N][N];
int dir[4][2]={{-1,0},{1,0},{0,-1},{0,1}};
struct node{
    int x;
    int y;
    int step;
}q[N*100];
template <typename T> void read(T &t){
	t=0;
	char ch=getchar();
	int f=1;
	while(ch<'0'||ch>'9'){
		if(ch=='-')f=-1;
		ch=getchar();
	}
	do{
		(t*=10)+=ch-'0';
		ch=getchar();
	}while(ch>='0'&&ch<='9');
	t*=f;
}
void bfs(int sx,int sy,int ex,int ey){
    int head=1,tail=1;
    bool flag=true;
    memset(vis,0,sizeof(vis));
    vis[sx][sy]=1;
    q[tail].x=sx;
    q[tail].y=sy;
    q[tail].step=0;
    tail++;
    while(head<tail){
        int x=q[head].x;
        int y=q[head].y;
        int step=q[head].step;
        if(x==ex&&y==ey){
            flag=false;
            printf("%d\n",step);
            break;
        }
        for(int i=0;i<4;i++){
            int nx=x+dir[i][0];
            int ny=y+dir[i][1];
            if(nx>=0&&nx<r&&ny>=0&&ny<c&&vis[nx][ny]==0&&a[nx][ny]=='.'){
                vis[nx][ny]=1;
                q[tail].x=nx;
                q[tail].y=ny;
                q[tail].step=step+1;
                tail++;
            }
        }
        head++;
    }
    if(flag)
        printf("-1\n");
}
int main(){
    int sx,sy,ex,ey;
    cin>>r>>c;
        for(int i=0;i<r;i++)
            scanf("%s",a[i]);
        for(int i=0;i<r;i++)
            for(int j=0;j<c;j++){
                if(a[i][j]=='@'){
                    sx=i;
                    sy=j;
                }
                if(a[i][j]=='*'){
                    ex=i;
                    ey=j;
                    a[i][j]='.';
                }
            }
        bfs(sx,sy,ex,ey);
    
	return 0;
}