#include <bits/stdc++.h>
//#include <conio.h>
using namespace std;
#define ll long long
const int N = 2e3 + 5;
const int di[] = {0, 0, 1, -1};
const int dj[] = {-1, 1, 0, 0};
const string C = "<>v^";
vector grid(N, string());
vector par(N, vector<int>(N, -1)), cost(N, vector<int>(N, 1e9));
int n, m, si, sj, ei, ej;
bool valid(int i, int j)
{
return i >= 0 && j >= 0 && i < n && j < m;
}
void dfs(int i, int j, vector<pair<int, int>> &ret)
{
ret.emplace_back(i, j);
for (int k = 0; k < 4; k++)
{
int ni = i + di[k], nj = j + dj[k];
if (valid(ni, nj) && grid[i][j] == C[k] && cost[ni][nj] > cost[i][j])
{
par[ni][nj] = k;
cost[ni][nj] = cost[i][j];
dfs(ni, nj, ret);
}
}
}
int bfs()
{
vector<array<int, 3>> q;
q.push_back({si, sj, 0});
par[si][sj] = -5;
cost[si][sj] = 0;
vector<pair<int, int>> cur;
for (int st = 0; st < q.size(); st++)
{
auto [i, j, c] = q[st];
dfs(i, j, cur);
for (auto [x, y] : cur)
{
for (int k = 0; k < 4; k++)
{
int ni = x + di[k], nj = y + dj[k];
if (valid(ni, nj) && cost[ni][nj] > c + 1)
{
par[ni][nj] = k;
cost[ni][nj] = c + 1;
q.push_back({ni, nj, c + 1});
}
}
}
cur.clear();
}
return cost[ei][ej];
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> m;
for (int i = 0; i < n; i++)
cin >> grid[i];
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m; j++)
{
if (grid[i][j] == 'o')
si = i, sj = j;
else if (grid[i][j] == 'x')
ei = i, ej = j;
}
}
cout << bfs() - 1 << endl;
while (par[ei][ej] != -5)
{
int k = par[ei][ej];
int i = ei - di[k], j = ej - dj[k];
grid[i][j] = C[k];
ei = i;
ej = j;
}
grid[si][sj] = 'o';
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m; j++)
{
cout << grid[i][j];
}
cout << '\n';
}
cout.flush();
system("pause");
return 0;
}
