#include <bits/stdc++.h>
#define F first
#define S second
#define tm itsnottime
using namespace std;
using ll = long long;
using db = long double;
const int sz = 1e2+4;
const int oo = 1e9+4;
const int mod = 1e9+9;
const int cfmod = 998244353;
const bool debug=0;

int n, m, h, sx, sy, endx, endy;
int ans[sz][sz][sz], p[sz][sz];
string g[sz];
int xx[5] = {-1,0,1,0,0};
int yy[5] = {0,-1,0,1,0};

void read() {
    cin>>n>>m>>h;
    for (int i=0; i<n; i++) {
        cin>>g[i];
        for (int j=0; j<m; j++)
            if (g[i][j]=='A') {
                sx = i; sy = j;
            } else if (g[i][j]=='B') {
                endx = i; endy = j;
            }
    }
    for (int i=0; i<n; i++)
        for (int j=0; j<m; j++)
            cin>>p[i][j];
}

bool ok(int x, int y) {
    return x<n && x>=0 && y<m && y>=0;
}

void sf() {
    for (int i=0; i<n; i++)
        for (int j=0; j<m; j++)
            fill(ans[i][j],ans[i][j]+sz,oo);
}


void bfs(char c) {
    sf();
    queue<pair<pair<int,int>,int> > q;
    ans[sx][sy][h] = 0;
    q.push({{sx,sy},h});
    while (!q.empty()) {
        int x = q.front().F.F, y = q.front().F.S, ch = q.front().S;
        q.pop();
        for (int i=0; i<5; i++) {
            int nx = x+xx[i], ny = y+yy[i], nh;
            if (!ok(nx,ny) || g[nx][ny]=='X') continue;
            if (g[nx][ny]==c) nh = min(h,ch+p[nx][ny]);
                else nh = ch-p[nx][ny];
            if (nh<1 || ans[nx][ny][nh]<ans[x][y][ch]+1) continue;
            ans[nx][ny][nh] = ans[x][y][ch]+1;
            q.push({{nx,ny},nh});
        }
    }
}

void print() {
    int res=oo;
    for (int i=1; i<=h; i++)
        res = min(res,ans[endx][endy][i]);
    if (res==oo) cout<<"impossible\n"; else cout<<res<<endl;
}

void solve() {
    read();
    if (debug) cout<<sx<<' '<<sy<<' '<<endx<<' '<<endy<<endl;
    if (debug) cout<<"ok read"<<endl;
    bfs('F');
    if (debug) cout<<"ok bfsF"<<endl;
    print();
    if (debug) cout<<"ok printF"<<endl;
    bfs('I');
    if (debug) cout<<"ok bfsI"<<endl;
    print();
    if (debug) cout<<"ok printI"<<endl;
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(NULL); cout.tie(NULL);
//    freopen("in.txt", "r", stdin);
//    freopen("out.txt", "w", stdout);
//    int t; cin>>t; while (t--)
    solve();
    return 0;
}