#include using namespace std; #ifdef DEBUG_ #include #else #define dump(...) #endif // clang-format off struct Fast{Fast(){std::cin.tie(0);ios::sync_with_stdio(false);}} fast; #define rep(i,n) for (int i=0; i<(int)n; ++i) #define rrep(i,a,n) for (int i=a; i<(int)n; ++i) #define out(msg) cout << (msg) << '\n' #define die(msg) do{ cout << (msg) << endl,exit(0); }while(0) #define el '\n' #define all(k) k.begin(), k.end() #define rall(k) k.rbegin(), k.rend() // const #define INFi 1 << 30 #define INFll 1LL << 60 #define MOD17 10'0000'0007 #define MOD98 9'9824'4353 // alias using ullint = unsigned long long int; using llint = long long int; template inline bool chmax(T& a, const T& b) { return ((a < b) ? (a = b, true) : false); } template inline bool chmin(T& a, const T& b) { return ((a > b) ? (a = b, true) : false); } // clang-format on int main() { int h, w; cin >> h >> w; vector grid(h); rep(i, h) cin >> grid[i]; rep(i, h) dump(grid[i]); auto dfs = [&](auto f, int y, int x, int jewel) -> int { // outbound if (!(0 <= y && y < h && 0 <= x && x < w)) return 0; // goal if (y == h - 1 && x == w - 1) { if (jewel >= 0) return 1; else return 0; } if (grid[y][x] == 'o') { jewel++; } else if (grid[y][x] == 'x') { jewel--; } else { return 0; // can't pass } if (jewel < 0) return 0; int cnt{}; if (y < h) cnt += f(f, y + 1, x, jewel); if (x < w) cnt += f(f, y, x + 1, jewel); return cnt; }; int cnt = dfs(dfs, 0, 0, 0); cout << cnt << el; }