var grid = require("fs").readFileSync("input.txt").toString().split("\n").filter(a=>(a)).reverse().map(a=>(a.split("")));
var dirs = [[0, 1], [1, 0], [0, -1], [-1, 0]];
var dir = 0;
var x = Math.floor(grid.length/2);
var y = Math.floor(grid.length/2);
var numInfected = 0;

for(var i = 0; i < 10000; i++){
	var clean = true;
	if(grid[y]){
		if(grid[y][x] == "#"){
			clean = false;
		}
	}
	else{
		grid[y] = [];
	}
	if(clean){
		grid[y][x] = "#";
		numInfected++;
		dir--;
	}
	else{
		grid[y][x] = ".";
		dir++;
	}
	dir = (dir+4)%4;
	x += dirs[dir][0];
	y += dirs[dir][1];
}
console.log(numInfected);