#include<bits/stdc++.h>
using namespace std;
int m,n;
const int N = 55;
int a[N][N];
int dx[4] = {0,0,1,-1};
int dy[4] = {1,-1,0,0};

struct node{
	int x,y,h;
	int step;
};
vector<node> v;

bool func(node a, node b){
	return a.h < b.h;
}

int bfs(int start_x,int start_y,int end_x,int end_y){
	if(start_x == end_x && start_y == end_y){
		return 0;
	}
	bool visited[55][55] = {false};
	queue<node> q;
	q.push({start_x,start_y,a[start_x][start_y]});
	int step = 0;
	visited[start_x][start_y] = 1;
	
	while(!q.empty()){
		node temp = q.front();
		q.pop();
		
		if(temp.x == end_x && temp.y == end_y)
			return temp.step;
		
		
		for(int i = 0 ; i < 4; i ++){
			int nx = temp.x + dx[i];
			int ny = temp.y + dy[i];
			
			if(nx >= 0 && nx < m && ny >= 0 && ny < n && a[nx][ny] != 0&&!visited[nx][ny]){
				visited[nx][ny] = 1;
				q.push({nx,ny,a[nx][ny],temp.step...