#include <iostream>
#include <vector>
#include <queue>
#include <utility>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n, m, t;
    while (cin >> n >> m >> t) {
        vector<string> grid(n);
        int sx = -1, sy = -1;
        int total = 0;

        // 读取地图并初始化
        for (int i = 0; i < n; ++i) {
            cin >> grid[i];
            for (int j = 0; j < (int)grid[i].size(); ++j) {
                if (grid[i][j] == '*') {
                    sx = i;
                    sy = j;
                }
                if (grid[i][j] != 'X') {
                    total++;
                }
            }
        }

        // 初始化距离数组，-1表示未被毒气覆盖
        vector<vector<int>> dist(n);
        for (int i = 0; i < n; ++i) {
            dist[i].assign(grid[i].size(), -1);
        }

        queue<pair<int, int>> q;
     ...