#include <bits/stdc++.h>
#define fore(i, a, b) for (int i = (a), _b = (b); i < _b; ++i)
#define fort(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define ford(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
#define fi first
#define se second
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define id(x, y) ((x) * c + (y))
#define row(p) ((p) / c)
#define column(p) ((p) % c)
using namespace std;
template<class A, class B> bool maxi(A &a, const B &b) {return (a < b) ? (a = b, true):false;};
template<class A, class B> bool mini(A &a, const B &b) {return (a > b) ? (a = b, true):false;};
typedef long long ll;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
const int maxR = 105, maxC = 105,
inf = 0x3f3f3f3f,
t[4][2] = {{0, 1}, {-1, 0}, {1, 0}, {0, -1} };
const char currents[4] = {'>', '^', 'v', '<'},
directions[4] = {'E', 'N', 'S', 'W'};//alphabetical order
int r, c, d[maxR][maxC];
char ocean[maxR][maxC];
//ii calm[maxR][maxC];
ii ducks;
//queue<ii> q;
deque<ii> dq;
//ii Calm(const int x, const int y) /*moving backward*/ {
// if (!calm[x][y].fi)/*not visited yet*/ {
// fore(i, 0, 4)
// if (ocean[x][y] == currents[i]) {
// return calm[x][y] = Calm(x - t[i][0], y - t[i][1]);
// }
// calm[x][y] = ii(x, y);
// };
// return calm[x][y];
//}
int main() {
#ifndef ONLINE_JUDGE
freopen("main.INP", "r", stdin);
#endif // ONLINE_JUDGE
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
memset(d, inf, sizeof(d));
cin >> r >> c;
fore(i, 0, r) {
cin >> ocean[i];
fore(j, 0, c)
if (ocean[i][j] == 'x') {
d[i][j] = 0;
// q.push(ii(i, j));
dq.pb(ii(i, j));
} else if (ocean[i][j] == 'o')
ducks = ii(i, j);
}
// while (!q.empty()) {
// const int u = q.front().fi, v = q.front().se;
// q.pop();
// fore(k, 0, 4) {
// const int x = u - t[k][0], y = v - t[k][1];
// const ii nxt = Calm(x, y);
// if (mini(d[nxt.fi][nxt.se], d[u][v] + 1))
// q.push(nxt);
// }
// }
while (!dq.empty()) {
const int u = dq.front().fi, v = dq.front().se;
dq.pop_front();
int x = -1, y = -1;
fore(i, 0, 4) {
x = u - t[i][0];
y = v - t[i][1];
if (x < 0 || y < 0 || x >= r || y >= c)
continue;
if (currents[i] == ocean[u][v]) {
if (mini(d[x][y], d[u][v]))
dq.push_front(ii(x, y));
} else {
if (mini(d[x][y], d[u][v] + 1))
dq.push_back(ii(x, y));
}
}
}
fore(x, 0, r) {
fore(y, 0, c)
if (d[x][y] == inf)
cerr << setw(3) << "oo ";
else
cerr << setw(3) << d[x][y] << ' ';
cerr << '\n';
}
if (d[ducks.fi][ducks.se] < inf) {
cout << ":)\n";
while (ocean[ducks.fi][ducks.se] != 'x') {
bool flag = true;
fore(i, 0, 4) {
if (ocean[ducks.fi][ducks.se] == currents[i]) {
flag = false;
// cerr << directions[i];
ducks.fi += t[i][0];
ducks.se += t[i][1];
break;
}
}
if (flag) {
int x, y;
fore(i, 0, 4) {
x = ducks.fi + t[i][0];
y = ducks.se + t[i][1];
if (x < 0 || y < 0 || x >= r || y >= c || d[ducks.fi][ducks.se] != d[x][y] + 1)
continue;
cout << directions[i];
ducks = ii(x, y);
break;
}
}
}
cout << '\n';
} else {
puts(":(");
}
return 0;
}
