#include<bits/stdc++.h>
using namespace std;
int n, m, q;
int a[1005][1005];
int p[1005][1005];
int s[1005][1005];
int ord[1005];
int rand(int l, int r){
    return 1ll * rand() * rand() % (r - l + 1) + l;
}
vector<int>t[1000005];
int cnt;
int rnk[1005];
void add(int x, int y, int xx, int yy){
    // cout << x << " " << y << " " << xx << " " << yy << endl;
    s[xx][yy]++;
    s[x - 1][y - 1]++;
    s[x - 1][yy]--;
    s[xx][y - 1]--;
}
void get(int h){
    for(int i = n; i >= 1; i--){
        p[h][i] = s[h][i];
        s[h - 1][i] += s[h][i];
        s[h][i - 1] += s[h][i];
        s[h - 1][i - 1] -= s[h][i];
        s[h][i] = 0;
    }
}
int o[1000005], tot;
int read(){
    int s = 0;
    char ch = getchar();
    while('0' > ch || ch > '9')ch = getchar();
    while('0' <= ch && ch <= '9'){
        s = s * 10 + ch - '0';
        ch = getchar();
    }
    return s;
}
signed main(){
    // freopen("similarity2.in", "r", stdin);
    // freopen("my.out", "w", stdout);
    srand(time(0));
    // double stt = clock();
    cin >> n >> m >> q;
    vector<int>r;
    for(int i = 1; i <= n; i++){
        for(int j = 1; j <= m; j++){
            a[i][j] = read();
            o[++tot] = a[i][j];
        }
    }
    sort(o + 1, o + 1 + tot);
    int len = 0;
    for(int i = 1; i <= tot; i++){
        if(i == 1 || o[i] != o[i - 1])o[++len] = o[i];
    }
    for(int i = 1; i <= n; i++){
        for(int j = 1; j <= m; j++){
            int l = 1, r = len;
            while(l <= r){
                int mid = l+r>>1;
                if(a[i][j] < o[mid]){
                    r = mid - 1;
                }else if(a[i][j] > o[mid]){
                    l = mid + 1;
                }else{
                    a[i][j] = mid;
                    break;
                }
            }
            t[a[i][j]].push_back(i);
        }
    }
    for(int i = 1; i <= n; i++)ord[i] = i;
    for(int i = 1; i + 1 <= n; i++){
        swap(ord[i], ord[rand(i + 1, n)]);
    }
    // for(int i = 1; i <= n; i++)cout << ord[i] << " ";
    // cout << endl;
    for(int i = 1; i <= n; i++)rnk[ord[i]] = i;
    bitset<1005>bit;
    // cout << "!" << endl;
    for(int i = 1; i <= 1000000; i++){
        bit.reset();
        for(int j = 0; j < t[i].size(); j++){
            bit[rnk[t[i][j]]] = 1;
        }
        vector<pair<int, int> > d;
        for(int j = bit._Find_first(); j != bit.size(); j = bit._Find_next(j)){
            if(!d.size())d.push_back(make_pair(j, j));
            else{
                if(bit[j - 1]){
                    d[d.size() - 1].second++;
                }else{
                    d.push_back(make_pair(j, j));
                }
            }
        }
        for(int j = 0; j < d.size(); j++){
            for(int k = 0; k < d.size(); k++){
                add(d[j].first, d[k].first, d[j].second, d[k].second);
            }
        }
    }
    for(int i = n; i >= 1; i--){
        get(i);
    }
    // for(int i = 1; i <= n; i++){
    //     for(int j = 1; j <= n; j++){
    //         cout << p[i][j] << " ";
    //     }
    //     cout << endl;
    // }
    while(q--){
        int x, y;
        x = read();
        y = read();
        x = rnk[x];
        y = rnk[y];
        if(x == y)p[x][y] = m;
        int fz = p[x][y];
        int fm = m * 2 - p[x][y];
        double ans = 1.0 * fz / fm;
        printf("%.10lf\n", ans);
    }
    // cerr << "MY:" << (double)(clock()) - stt << endl;
    return 0;
}