#include <cstdio>#include <cstring>#include <iostream>#include <map>#include <set>#include <vector>#include <string>#include <queue>#include <deque>#include <bitset>#include <list>#include <cstdlib>#include <climits>#include <cmath>#include <ctime>#include <algorithm>#include <stack>#include <sstream>#include <numeric>#include <fstream>#include <functional>using namespace std;#define MP make_pair#define PB push_backtypedef long long LL;typedef unsigned long long ULL;typedef vector<int> VI;typedef pair<int,int> pii;const int INF = INT_MAX / 3;const double eps = 1e-8;const LL LINF = 1e17;const double DINF = 1e60;const int maxn = 25;const int maxk = 10;const int dx[] = {0,0,1,-1};const int dy[] = {1,-1,0,0};char mp[maxn][maxn];int n,m,t,sx,sy,ex,ey;int dist[maxn][maxn][1 << maxk];struct Node {    int x,y,state;    Node(int x,int y,int state): x(x), y(y), state(state) {}};int solve() {    queue<Node> q;    q.push(Node(sx,sy,0));    dist[sx][sy][0] = 0;    int x,y,nx,ny,s,ns;    while(!q.empty()) {        Node now = q.front(); q.pop();        x = now.x; y = now.y; s = now.state;        if(dist[x][y][s] == t) continue;        if(x == ex && y == ey) return dist[x][y][s];        for(int i = 0;i < 4;i++) {            nx = x + dx[i];            ny = y + dy[i];            ns = s;            char nc = mp[nx][ny];            if(nc == ‘*‘) continue;            if(nc >= ‘A‘ && nc <= ‘J‘ && !(s & (1 << (nc - ‘A‘)))) continue;            if(nc >= ‘a‘ && nc <= ‘j‘) ns |= (1 << (nc - ‘a‘));            if(dist[nx][ny][ns] == -1 || dist[nx][ny][ns] > dist[x][y][s] + 1) {                dist[nx][ny][ns] = dist[x][y][s] + 1;                q.push(Node(nx,ny,ns));            }        }    }    return -1;}int main() {    while(scanf("%d%d%d",&n,&m,&t) != EOF) {        memset(mp,‘*‘,sizeof(mp));        memset(dist,-1,sizeof(dist));        for(int i = 1;i <= n;i++) {            for(int j = 1;j <= m;j++) {                scanf(" %c",&mp[i][j]);                if(mp[i][j] == ‘@‘) {                    sx = i; sy = j; mp[i][j] = ‘.‘;                }                else if(mp[i][j] == ‘^‘) {                    ex = i; ey = j; mp[i][j] = ‘.‘;                }            }        }        printf("%d\n",solve());    }    return 0;}