const BKRT = "\n";
const SPAC = " ";
const NOSP = "";

function Main(input){
	input = [].concat(...input.split(BKRT).map(a=>a.split(SPAC)));
  const strShift = ()=>input.shift();
  const intShift = ()=>~~input.shift();
  
  var A = intShift();
  var B = strShift();
  var o = [];
  
  var s = 0;
  
  for(var i = 0; i < A; i++){
  	if(B[i] == ".")s++;
  }
  o.push(s);
  for(var i = 0; i < A; i++){
  	if(B[i] == "."){
    	s--;
    }else{
    	s++;
    }
    o.push(s);
  }
  
  return ~~Math.min(...o);
}

// If you are interested in the algorithms I used, 
// there is no need to read down from this line.

((b,c,d)=>"undefined"!=typeof require?console.log(Main(require("fs").readFileSync("/dev/stdin","utf8"))):[b=b.split("\n").slice(1,-1).join("\n"),c=function(){try{return Main(b)}catch(f){return f.stack||f.message}}(),d=typeof c,"string"==d||(c=JSON.stringify(c)),$("<form>").append([[10,b],0,[1,d],0,[10,c]].map(f=>$(f?"<textarea>":"<br>",f&&{rows:f[0],cols:40,text:f[1]}))).appendTo("body")])(`
5
#.##.
`);