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 readV(T...)(ref T t){auto r=rdsp;foreach(ref v;t)pick(r,v);}

void main()
{
  string s; readV(s);

  auto u = s[0..2].to!int, v = s[2..4].to!int;
  if (1 <= u && u <= 12 && 1 <= v && v <= 12)
    writeln("AMBIGUOUS");
  else if (1 <= u && u <= 12)
    writeln("MMYY");
  else if (1 <= v && v <= 12)
    writeln("YYMM");
  else
    writeln("NA");
}
