// hrbust 1621 迷宫问题II

// 优先队列——广搜

// 什么时候需要回溯什么时候不需要？

#include <stdio.h>

#include <string.h>

#include <iostream>

#include <queue>

using namespace std;

#define maxn 100000

char mp[][];

int dir[][] = {, , -, , , , , -};

int vis[][];

int r, c;

int step[][];

int stx, sty, edx, edy;

bool check(int x, int y) {

    if (x >=  && x < r && y >=  && y < c && !vis[x][y] && mp[x][y] != '#')

        return true;

    return false;

}

struct Node {

    friend bool operator < (Node n1, Node n2)

    {

        return step[n1.x][n1.y] > step[n2.x][n2.y];//"<"为从大到小排列，">"为从小打到排列

    }

    int x, y;

}node[];

priority_queue<Node> qn;

void bfs(int x, int y) {

    int head = , tail = ;

    memset(vis, , sizeof(vis));

    for (int i=; i<r; ++i) {

        for (int j=; j<c; ++j) {

            step[i][j] = maxn;

        }

    }

    while(!qn.empty()) {

        qn.pop();

    }

    vis[x][y] = ;

    step[x][y] = ;

    Node temp;

    temp.x = x;

    temp.y = y;

   // node[tail++] = temp;

   qn.push(temp);

    //while(head < tail) {

    while(!qn.empty()) {

        //Node now = node[head++];

        Node now = qn.top();

        qn.pop();

        for (int i=; i<; ++i) {

            temp.x = now.x + dir[i][];

            temp.y = now.y + dir[i][];

            int tstep = ;

            if (check(temp.x, temp.y)) {

                if (mp[temp.x][temp.y] >= '' && mp[temp.x][temp.y] <= '')

                    tstep = mp[temp.x][temp.y] - '' + ;

                else tstep = ;

                step[temp.x][temp.y] = min(step[temp.x][temp.y], step[now.x][now.y] + tstep);

                vis[temp.x][temp.y] = ;

                //node[tail++] = temp;

                qn.push(temp);

                if (temp.x == edx && temp.y == edy) break;

            }

        }

    }

    return;

}

int main() {

    int t;

    cin >> t;

    while(t--) {

        cin >> r >> c;

        for (int i=; i<r; ++i) {

            for (int j=; j<c; ++j) {

                cin >> mp[i][j];

                if (mp[i][j] == 'Z') {

                    stx = i, sty = j;

                }

                else if (mp[i][j] == 'W') {

                    edx = i, edy = j;

                }

            }

        }

        bfs(stx, sty);

        int ans = step[edx][edy];

        if (ans == maxn) {

            cout << "IMPOSSIBLE\n";

        }

        else cout << ans << endl;

    }

    return ;

}