import std.algorithm, std.container, std.conv, std.math, std.range, std.typecons, std.stdio, std.string;

auto rdsp(){return readln.splitter;}
void pick(R,T)(ref R r,ref T t){t=r.front.to!T;r.popFront;}
void pickV(R,T...)(ref R r,ref T t){foreach(ref v;t)pick(r,v);}
void readV(T...)(ref T t){auto r=rdsp;foreach(ref v;t)pick(r,v);}

void main()
{
  int n, m; readV(n, m);

  auto c = new int[](m+1);
  foreach (i; 0..n) {
    auto rd = rdsp;
    int k; pickV(rd, k);
    foreach (j; 0..k) {
      int a; pickV(rd, a);
      ++c[a];
    }
  }

  writeln(c.count(n));
}
