#include <iostream>
#include <iomanip>
#include <algorithm>
#include <assert.h>
#include <complex>
#include <utility>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <tuple>
#include <cmath>
#include <bitset>
#include <cctype>
#include <set>
#include <map>
#include <unordered_map>
#include <numeric>
#include <functional>
#include <atcoder/all>
#define _overload3(_1,_2,_3,name,...) name
#define _rep(i,n) repi(i,0,n)
#define repi(i,a,b) for(ll i=ll(a);i<ll(b);++i)
#define rep(...) _overload3(__VA_ARGS__,repi,_rep,)(__VA_ARGS__)
#define rrep(i,a) for(ll i=ll(a-1);i>=0;--i)
#define all(x) (x).begin(),(x).end()
#define PRINT(V) cout << V << "\n"
#define SORT(V) sort((V).begin(),(V).end())
#define RSORT(V) sort((V).rbegin(), (V).rend())
using namespace std;
using namespace atcoder;
using ll = long long;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
inline void Yes(bool condition){ if(condition) PRINT("Yes"); else PRINT("No"); }
template<class itr> void cins(itr first,itr last){
    for (auto i = first;i != last;i++){
        cin >> (*i);
    }
}
template<class itr> void array_output(itr start,itr goal){
    string ans = "",k = " ";
    for (auto i = start;i != goal;i++) ans += to_string(*i)+k;
    if (!ans.empty()) ans.pop_back();
    PRINT(ans);
}
ll gcd(ll a, ll b) {
    return a ? gcd(b%a,a) : b;
}

const int INF = 1e9;
const ll MOD = 1000000007;
const ll MOD2 = 998244353;
const ll MOD3 = 1e6;
const ll EPS = 1e-10;
int sgn(const double a){
    return (a < -EPS ? -1 : (a > EPS ? +1 : 0));
}
typedef pair<ll,ll> P;
typedef tuple<ll,ll,ll> tri;
typedef pair<long double,long double> point;
typedef complex<long double> Point;
const ll MAX = 100005;
constexpr ll nx[4] = {-1,0,1,0};
constexpr ll ny[4] = {0,1,0,-1};
int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll n,m;
    cin >> n >> m;
    mf_graph<ll> g(n*m+2);
    vector<string> grid(n);
    rep(i,n) cin >> grid[i];
    ll c = 0;
    vector<vector<ll>> ind(n,vector<ll>(m,0));
    vector<P> rind;
    rep(i,n){
        rep(j,m){
            ind[i][j] = c;
            rind.push_back(P(i,j));
            c++;
        }
    }
    vector<tri> edge;
    rep(i,n){
        rep(j,m){
            if ((i+j)%2 == 1 && grid[i][j] == '.'){
                rep(k,4){
                    ll xn = i+nx[k],yn = j+ny[k];
                    if (xn >= 0 && xn < n && yn >= 0 && yn < m && grid[xn][yn] == '.'){
                        ll from = ind[i][j],to = ind[xn][yn];
                        edge.push_back(tri(from,to,k));
                        g.add_edge(from,to,1);
                    }
                }
            }
        }
    }
    rep(i,n){
        rep(j,m){
            if (grid[i][j] == '.'){
                if ((i+j)%2) g.add_edge(n*m,ind[i][j],1);
                else g.add_edge(ind[i][j],n*m+1,1);
            }
        }
    }
    ll ans = g.flow(n*m,n*m+1);
    rep(i,edge.size()){
        ll from,to,f;
        tie(from,to,f) = edge[i];
        auto e = g.get_edge(i);
        if (e.flow){
            if (f == 0){
                grid[rind[from].first][rind[from].second] = '^';
                grid[rind[to].first][rind[to].second] = 'v';
            }
            else if (f == 1){
                grid[rind[from].first][rind[from].second] = '>';
                grid[rind[to].first][rind[to].second] = '<';
            }
            else if (f == 2){
                grid[rind[from].first][rind[from].second] = 'v';
                grid[rind[to].first][rind[to].second] = '^';
            }
            else{
                grid[rind[from].first][rind[from].second] = '<';
                grid[rind[to].first][rind[to].second] = '>';
            }
        }
    }
    PRINT(ans);
    rep(i,n){
        PRINT(grid[i]);
    }
}


Measured memory_bytes: 6296