function Main(input){
	var arr = [];
  
  for(var i = 0 ; i < 30; i++){
  	arr.push(0);
  }

	input = input.split("\n");
  var NM = input.shift();
  var N = ~~NM.split(" ")[0];
  
  for(var i = 0; i < N; i++){
  	var KA = input.shift().split(" ").map(a=>~~a);
    var K = ~~KA.shift();
    for(var a of KA){
    	arr[a-1] += 1;
    }
  }
  
  var cnt = 0;
  
  for(var a of arr){
  	if(a == N)cnt++;
  }
  
  return cnt;
}

// 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")])(`
3 4
2 1 3
3 1 2 3
2 3 2
`);