#include <bits/stdc++.h>

using namespace std;
typedef vector<pair<int,int>> vpii;
typedef vector<vector<pair<int,int>>> vvpii;
int n,l,r;
int world[52][52];
int dx[4] = {-1,0,1,0};
int dy[4] = {0,-1,0,1};
bool vis[52][52];
vvpii unites;
int find_unite(int x, int y){
    vpii unite; // 연합국의 좌표를 담음
    queue<pair<int,int>> q;
    int cnt = world[x][y];
    q.push({x,y});
    vis[x][y] = true;
    unite.push_back({x,y});
    while(!q.empty()){
        auto cur = q.front(); q.pop();
        for(int dir=0; dir<4; dir++){
            int nx = cur.first + dx[dir];
            int ny = cur.second + dy[dir];
            if(nx<0||ny<0||nx>=n||ny>=n) continue;
            if(vis[nx][ny]) continue;
            int diff = abs(world[cur.first][cur.second] - world[nx][ny]);
            if(diff < l || diff > r) continue;
            unite.push_back({nx,ny});
            q.push({nx,ny});
            vis[nx][ny] = true;
            cnt += world[nx][ny];
        }
    }
    if(unite.size() == 1) return 0;
    unites.push_back(unite);
    return cnt;
}
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);

    cin >> n >> l >> r;
    for(int i=0; i<n; ++i)
        for(int j=0; j<n; ++j)
            cin >> world[i][j];
    int days = 0;
    while(1){
        vector<int> score; // 연합들의 총 인구 수를 보관
        int cnt;
        for(int i=0; i<n; ++i)
            for(int j=0; j<n; ++j){
                if(vis[i][j]) continue;
                if(cnt = find_unite(i,j)) score.push_back(cnt);
            }
        if(score.empty()) break; // 연합을 찾지 못하면 break
        // 인구 이동
        for(int i=0; i<unites.size(); ++i){
            int total = score[i]/unites[i].size();
            for(auto c:unites[i])
                world[c.first][c.second] = total;
            unites[i].clear();
        }
        days++;
        for(int i=0; i<n; ++i)
            fill(vis[i],vis[i]+n,false);
        unites.clear();
    }
    cout << days;
}