#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define i128 __int128
#define mem(x) memset(x,0,sizeof(x))
#define endl "\n"
#define printYes cout << "Yes\n"
#define printYES cout << "YES\n"
#define printNo cout << "No\n"
#define printNO cout << "NO\n"
#define lowbit(x) ((x)&(-(x)))
#define pb push_back
#define mkp make_pair
#define pii pair<int,int>
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
#define rep(i,j,k) for (int i=(j);i<=(k);i++)
#define per(i,j,k) for (int i=(j);i>=(k);i--)
#define pcnt(x) __builtin_popcount(x)
mt19937 rnd(time(0));
template<class T>void chkmin(T&x,T y){x=min(x,y);}
template<class T>void chkmax(T&x,T y){x=max(x,y);}

const ll inf=1000000000000000000; 
//const ll inf=1000000000;
//const ll mod=998244353;
//const ll mod=1000000007;

const int N=1005;
double alpha=0.5;
int n,m,q,cnt,B; 
int a[N][N],ans[N][N],top[N*N];
int c[N*N];
vector<int>b[N*N];
int id[N];

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);cout.tie(0);
	cin >> n >> m >> q;
	rep(i,1,n) rep(j,1,m) cin >> a[i][j];
	rep(i,1,n) rep(j,1,m) c[++cnt]=a[i][j];
	sort(c+1,c+cnt+1);
	cnt=unique(c+1,c+cnt+1)-c-1;
	rep(i,1,n) rep(j,1,m) a[i][j]=lower_bound(c+1,c+cnt+1,a[i][j])-c,b[a[i][j]].pb(i);
	B=m*alpha;
	if (B<=10) B=m;
	alpha=1.0*B/m;
	rep(i,1,n)
	{
		rep(j,1,m) id[j]=j;
		shuffle(id+1,id+m+1,rnd);
		rep(j,1,B)
		{
			int col=a[i][id[j]],len=SZ(b[col]);
			rep(k,top[col],len-1) ans[i][b[col][k]]++;
		}
		rep(j,1,m) top[a[i][j]]++;
	}
	rep(i,1,q)
	{
		int x,y;
		cin >> x >> y;
		if (x>y) swap(x,y);
		if (x==y) cout << "1\n";
		else 
		{
			double r=2*m-ans[x][y]/alpha;
			double res=2.0*m/r-1;
			cout << fixed << setprecision(10) << res << endl;
		}
	}
	return 0;
}