# include <iostream>
# include <algorithm>
# include <vector>
# include <string>
# include <set>
# include <map>
# include <cmath>
# include <iomanip>
# include <functional>
# include <utility>
# include <stack>
# include <queue>
# include <list>
# include <tuple>
# include <unordered_map>
# include <numeric>
# include <complex>
# include <bitset>
using namespace std;
using LL = long long;
using ULL = unsigned long long;
typedef pair<LL, LL> P;
constexpr int INF = 2000000000;
constexpr int HINF = INF / 2;
constexpr double DINF = 100000000000000000.0;
constexpr long long LINF = 9223372036854775807;
constexpr long long HLINF = 4500000000000000000;
constexpr long long MMOD = 500000004;
const double PI = acos(-1);
int dx[4] = { 0,1,0,-1 }, dy[4] = { 1,0,-1,0 };
# define ALL(x)      (x).begin(),(x).end()
# define UNIQ(c)     (c).erase(unique(ALL((c))), end((c)))
# define mp          make_pair
# define eb          emplace_back
# define FOR(i,a,b)  for(int i=(a);i<(b);i++)
# define RFOR(i,a,b) for(int i=(a);i>=(b);i--)
# define REP(i,n)    FOR(i,0,n)
# define INIT        std::ios::sync_with_stdio(false);std::cin.tie(0)

string s;

int main() {
	cin >> s;
	int ocount = 0, xcount = 0;
	REP(i, s.size()) {
		if (i) {
			if (s[i] == s[i - 1] && s[i] == 'X') {
				ocount = 0;
				xcount++;
				if (xcount == 3) {
					cout << "West" << endl;
					return 0;
				}
			}else if (s[i] == s[i - 1] && s[i] == 'O') {
				xcount = 0;
				ocount++;
				if (ocount == 3) {
					cout << "West" << endl;
					return 0;
				}
			}
			else {
				xcount = 0, ocount = 0;
			}
		}
		else {
			if (s[i] == 'X')xcount++;
			else ocount++;
		}
	}
	cout << "NA" << endl;
}