import core.bitop;
import std.algorithm;
import std.ascii;
import std.bigint;
import std.conv;
import std.functional;
import std.math;
import std.numeric;
import std.range;
import std.stdio;
import std.string;
import std.random;
import std.typecons;
import std.container;

alias sread = () => readln.chomp();
alias Point2 = Tuple!(long, "y", long, "x");

T lread(T = long)()
{
    return readln.chomp.to!T();
}

T[] aryread(T = long)()
{
    return readln.split.to!(T[])();
}

void scan(TList...)(ref TList Args)
{
    auto line = readln.split();
    foreach (i, T; TList)
    {
        T val = line[i].to!(T);
        Args[i] = val;
    }
}

void main()
{
    auto s = sread();
    auto a = s[0 .. 2].to!(long);
    auto b = s[2 .. 4].to!(long);
    if(a <= 12 && b <= 12)
    {
        if(a == 0 && b == 0)
        {
			writeln("NA");
        }
        else if(a == 0)
        {
            writeln("YYMM");
        }
        else if(b == 0)
        {
            writeln("MMYY");
        }
        else
        {
            writeln("AMBIGUOUS");
        }
    }
    else if(a > 12)
    {
        if(b == 0 || b > 12)
        {
            writeln("NA");
        }
        else
        {
            writeln("YYMM");
        }
    }
    else
    {
        if(a == 0 || a > 12)
        {
            writeln("NA");
        }
        else
        {
            writeln("MMYY");
        }
    }
}
