#include <cstdio>
#include <algorithm>
#define N 1111
using namespace std;

int up[N][N],left[N][N],down[N][N],right[N][N],l[N],r[N],n,m,ptr,mink,ans,kol;
char c[N][N];
int s[N];

pair<int,int> times[N];

inline int prev(int x){
    return x&(x-1);
}

inline int next(int x){
    return (x<<1)-(x&(x-1));
}

inline void modify(int pos,int value){
    for (;pos<N;pos=next(pos)) s[pos]+=value;
}

inline int get_sum(int l,int r){
    if (l>r) return 0;
    int k=0,p;
    for (p=r;p>0;p=prev(p)) k+=s[p];
    for (p=l-1;p>0;p=prev(p)) k-=s[p];
    return k;
}

inline void input(){
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
    scanf("%d%d%d\n",&n,&m,&mink);
    mink=mink%4?mink/4+2:mink/4+1;
    for (int i=1;i<=n;i++){
        for (int j=1;j<=m;j++) scanf("%c",&c[i][j]);
        scanf("\n");
    }
}

inline void init(){
    for (int i=1;i<=n;i++)
        for (int j=1;j<=m;j++){
            up[i][j]=c[i][j]=='#'?0:up[i-1][j]+1;
            left[i][j]=c[i][j]=='#'?0:left[i][j-1]+1;
        }
    for (int i=n;i>=1;i--)
        for (int j=m;j>=1;j--){
            down[i][j]=c[i][j]=='#'?0:down[i+1][j]+1;
            right[i][j]=c[i][j]=='#'?0:right[i][j+1]+1;
        }
}

inline void upd_ans(){
    memset(s,0,sizeof(s));
    kol=0;
    for (int i=1;i<=ptr;i++){
        if (l[i]>=mink){
            modify(i,1);
            times[++kol]=make_pair(l[i]+i-1,i);
        }
    }
    sort(times+1,times+kol+1);
    int f=1;
    for (int i=1;i<=ptr;i++){
        ans+=get_sum(i-r[i]+1,i-mink+1);
        while (times[f].first==i && f<=kol){
            modify(times[f].second,-1);
            ++f;
        }
    }
}

int main(){
    input();
    init();
    for (int I=1;I<=n;I++){
        ptr=0;
        for (int i=I,j=1;i<=n && j<=m;i++,j++){
            l[++ptr]=min(right[i][j],down[i][j]);
            r[ptr]=min(left[i][j],up[i][j]);
        }
        upd_ans();
    }
    for (int I=2;I<=m;I++){
        ptr=0;
        for (int i=1,j=I;i<=n && j<=m;i++,j++){
            l[++ptr]=min(right[i][j],down[i][j]);
            r[ptr]=min(left[i][j],up[i][j]);
        }
        upd_ans();
    }
    printf("%d",ans);
}