#include <bits/stdc++.h>
using namespace std;
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
 
#define ms(s, n) memset(s, n, sizeof(s))
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define FORd(i, a, b) for (int i = (a) - 1; i >= (b); --i)
#define FORall(it, a) for (__typeof((a).begin()) it = (a).begin(); it != (a).end(); it++)
#define sz(a) int((a).size())
#define present(t, x) (t.find(x) != t.end())
#define all(a) (a).begin(), (a).end()
#define uni(a) (a).erase(unique(all(a)), (a).end())
#define pb push_back
#define pf push_front
#define mp make_pair
#define fi first
#define se second
#define prec(n) fixed<<setprecision(n)
#define bit(n, i) (((n) >> (i)) & 1)
#define bitcount(n) __builtin_popcountll(n)
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pi;
typedef vector<int> vi;
typedef vector<pi> vii;
const int MOD = (int) 1e9 + 7;
const int FFTMOD = 119 << 23 | 1;
const int INF = (int) 1e9 + 23111992;
const ll LINF = (ll) 1e18 + 23111992;
const ld PI = acos((ld) -1);
const ld EPS = 1e-9;
inline ll gcd(ll a, ll b) {ll r; while (b) {r = a % b; a = b; b = r;} return a;}
inline ll lcm(ll a, ll b) {return a / gcd(a, b) * b;}
inline ll fpow(ll n, ll k, int p = MOD) {ll r = 1; for (; k; k >>= 1) {if (k & 1) r = r * n % p; n = n * n % p;} return r;}
template<class T> inline int chkmin(T& a, const T& val) {return val < a ? a = val, 1 : 0;}
template<class T> inline int chkmax(T& a, const T& val) {return a < val ? a = val, 1 : 0;}
inline ull isqrt(ull k) {ull r = sqrt(k) + 1; while (r * r > k) r--; return r;}
inline ll icbrt(ll k) {ll r = cbrt(k) + 1; while (r * r * r > k) r--; return r;}
inline void addmod(int& a, int val, int p = MOD) {if ((a = (a + val)) >= p) a -= p;}
inline void submod(int& a, int val, int p = MOD) {if ((a = (a - val)) < 0) a += p;}
inline int mult(int a, int b, int p = MOD) {return (ll) a * b % p;}
inline int inv(int a, int p = MOD) {return fpow(a, p - 2, p);}
inline int sign(ld x) {return x < -EPS ? -1 : x > +EPS;}
inline int sign(ld x, ld y) {return sign(x - y);}
mt19937 mt(chrono::high_resolution_clock::now().time_since_epoch().count());
inline int mrand() {return abs((int) mt());}
inline int mrand(int k) {return abs((int) mt()) % k;}
#define db(x) cerr << "[" << #x << ": " << (x) << "] ";
#define endln cerr << "\n"; 

void chemthan() {
    int test; cin >> test;
    FOR(it, 1, test + 1) {
        db(it) endln;
        cout << "Case #" << it << ": ";
        int n, m, k, l; cin >> n >> m >> k >> l, k--;
        vector<string> s(n);
        FOR(i, 0, n) cin >> s[i];
        vii changes(l);
        FOR(i, 0, l) {
            int u, v; cin >> u >> v; u--, v--;
            changes[i] = mp(u, v);
        }
        {
            vector<string> ss = vector<string>(m);
            FOR(i, 0, m) {
                FOR(j, 0, n) ss[i] += s[j][i];
            }
            s = ss;
        }
        auto solve = [&] () {
            int C = min(n, m) + 5;
            vector<vi> fen(m, vi(n + 5));
            auto upd = [&] (vi& fen, int p, int v) {
                p++;
                for (; p < sz(fen); p += p & -p) {
                    fen[p] += v;
                }
            };
            auto query = [&] (vi& fen, int p) {
                p++;
                chkmin(p, sz(fen) - 1);
                int res = 0;
                for (; 0 < p; p -= p & -p) {
                    res += fen[p];
                }
                return res;
            };
            FOR(i, 0, m) FOR(j, 0, n) {
                if (s[i][j] == 'X') {
                    upd(fen[i], j, 1);
                }
            }
            vi f(C);
            auto ss = s;
            auto upd_col = [&] (int col, int s) {
                int sum = query(fen[col], k - 1);
                FOR(i, 0, C) {
                    if (k + i < n) {
                        sum += ss[col][k + i] == 'X';
                    }
                    if (k + i < n && ss[col][k + i] == 'X') {
                        f[i] += s;
                    }
                    else {
                        if (k + 1 <= sum) {
                            f[i] += s;
                        }
                    }
                }
            };
            FOR(i, 0, m) upd_col(i, 1);
            vi res;
            for (auto [u, v] : changes) {
                upd_col(v, -1);
                if (ss[v][u] == '.') {
                    ss[v][u] = 'X';
                    upd(fen[v], u, 1);
                }
                else {
                    ss[v][u] = '.';
                    upd(fen[v], u, -1);
                }
                upd_col(v, +1);
                res.pb(INF);
                FOR(i, 0, C) chkmin(res.back(), f[i] + i);
            }
            return res;
        };
        vi res(l, INF);
        FOR(it, 0, 2) {
            auto tmp = solve();
            FOR(i, 0, l) chkmin(res[i], tmp[i]);
            FOR(i, 0, m) reverse(all(s[i]));
            for (auto& [u, v] : changes) {
                u = n - u - 1;
            }
            k = n - k - 1;
        }
        cout << accumulate(all(res), 0LL) << "\n";
    }
}

int32_t main(int32_t argc, char* argv[]) {
    ios_base::sync_with_stdio(0), cin.tie(0);
    if (argc > 1) {
        assert(freopen(argv[1], "r", stdin));
    }
    if (argc > 2) {
        assert(freopen(argv[2], "wb", stdout));
    }
    chemthan();
    cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
    return 0;
}