#include<bits/stdc++.h>

using namespace std;

const int INF = 0x3fffffff;

const int maxn = ;

#define PB push_back

struct Edge

{

    int from,to,cap,flow;

};

vector<Edge> edges;

vector<int> G[maxn];

int S ,T ;

void AddEdge(int from,int to,int cap)

{

    edges.PB(Edge{from,to,cap,});

    edges.PB(Edge{to,from,,});

    int m = edges.size();

    G[from].PB(m-);

    G[to].PB(m-);

}

bool vis[maxn];

int d[maxn],cur[maxn];

bool bfs()

{

    memset(vis,,sizeof(vis));

    queue<int> q;

    q.push(S);

    d[S] = ;

    vis[S] = true;

    while(q.size()){

        int u = q.front(); q.pop();

        for(int i = ; i < G[u].size(); i++){

            Edge &e = edges[G[u][i]];

            if(!vis[e.to] && e.cap > e.flow){

                vis[e.to] = true;

                d[e.to] = d[u] + ;

                q.push(e.to);

            }

        }

    }

    return vis[T];

}

int dfs(int u,int a)

{

    if(u == T || a == ) return a;

    int flow = , f;

    for(int &i = cur[u]; i < G[u].size(); i++){

        Edge &e = edges[G[u][i]];

        if(d[u] +  == d[e.to] && (f = dfs(e.to,min(a,e.cap-e.flow))) >){

            e.flow += f;

            edges[G[u][i]^].flow -= f;

            flow += f;

            a -= f;

            if(a == ) break;

        }

    }

    return flow;

}

int MaxFlow()

{

    int flow = ;

    while(bfs()){

        memset(cur,,sizeof(cur));

        flow += dfs(S,INF);

    }

    return flow;

}

typedef pair<int,int> pii;

#define fi first

#define se second

#define MP make_pair

vector<pii> vec;

const int N = ;

char s[N][N];

int id[N][N];

int dx[] = {,,-,};

int dy[] = {,-,,};

int main()

{

    //freopen("in.txt","r",stdin);

    int n,m; scanf("%d%d",&n,&m);

    int Icnt = , Wcnt = , Ncnt = ;

    for(int i = ; i <= n; i++){

        scanf("%s",s[i]+);

        for(int j = ; j <= m; j++){

            if(s[i][j] == 'I'){

                vec.PB(MP(i,j));

                id[i][j] = Icnt++;

            }

            if(s[i][j] == 'W'){

                id[i][j] = Wcnt++;

            }

            if(s[i][j] == 'N'){

                id[i][j] = Ncnt++;

            }

        }

    }

    int MW = Icnt*  + ;

    int MN = MW + Wcnt + ;

    S = MN +Ncnt + ; T = MN +Ncnt + ;

    for(int i = ; i < vec.size(); i++){

        int x = vec[i].fi, y = vec[i].se;

        int in = *i+, out = *i+;

        AddEdge(in,out,);

        for(int k = ; k < ; k++){

            int nx = x+dx[k], ny = y+dy[k];

            if(s[nx][ny] == 'W'){

                int u = id[nx][ny]+MW;

                AddEdge(u,in,);

            }

            if(s[nx][ny] == 'N'){

                int v = id[nx][ny]+MN;

                AddEdge(out,v,);

            }

        }

    }

    for(int i = ; i <= n; i++)

        for(int j = ; j <= m; j++){

            if(s[i][j] == 'W'){

                int v = id[i][j]+MW;

                AddEdge(S,v,);

            }

            if(s[i][j] == 'N'){

                int u = id[i][j]+MN;

                AddEdge(u,T,);

            }

        }

    int ans = MaxFlow();

    printf("%d",ans);

    return ;

}