#include <bits/stdc++.h>
using namespace std;
#define int long long
const int inf=1e12;
signed main(){
int n,m; cin>>n>>m;
vector<vector<char>> a(n,vector<char>(m));
int sR, sC, eR, eC;
for (int i=0; i<n; i++) for (int j=0; j<m; j++) {
cin>>a[i][j];
if (a[i][j]=='o') sR=i, sC=j;
if (a[i][j]=='x') eR=i, eC=j;
}
char best='x';
int ans=inf;
queue<pair<int,int>> q;
for (int dr=-1; dr<=1; dr++){
for (int dc=-1; dc<=1; dc++){
if (sR+dr<n and sC+dc<m and sR+dr>=0 and sC+dc>=0 and (abs(dr)+abs(dc)==1)){
bool ok=false;
q.push({sR+dr,sC+dc});
int cnt=1;
while(!q.empty()){
cnt++;
auto [r,c] = q.front(); q.pop();
if (a[r][c]=='^') q.push({r-1,c});
else if (a[r][c]=='>') q.push({r,c+1});
else if (a[r][c]=='<') q.push({r,c-1});
else if (a[r][c]=='v') q.push({r+1,c});
else if (a[r][c]=='x'){
ok=true;
break;
}
}
char dir = 'x';
if (dr==1) dir='S';
if (dr==-1) dir='N';
if (dc==1) dir='E';
if (dc==-1) dir='W';
if (ok and (cnt<ans or cnt==ans and dir<best)){
ans=cnt;
if (dr==1) best='S';
if (dr==-1) best='N';
if (dc==1) best='E';
if (dc==-1) best='W';
}
}
}
}
if (best=='x'){
cout<<":(\n";
}else{
cout<<":)\n";
cout<<best<<'\n';
}
}
