#include<cstdio>
int n,m,k,i,j,u;
char s[205][205][12],c;
bool cmp(int x0,int y0,int x1,int y1){
    for(int i=0;i<k;++i)if(s[x0][y0][i]!=s[x1][y1][i])return 0;
    return 1;
}
int main(){
    scanf("%d%d%d",&n,&m,&k);
    for(i=0;i<n;++i){
        for(j=0;j<m;++j){
            while(c<33||c>126)c=getchar();
            for(u=0;u<k;++u)s[i][j][u]=c,c=getchar();
        }
    }
    if(!cmp(0,0,0,1)){
        if(cmp(0,0,1,0))puts("1 2");
        else puts("1 1");
        return 0;
    }
    for(i=0;i<n;++i)
    for(j=0;j<m;++j)if(!cmp(0,0,i,j))printf("%d %d\n",i+1,j+1);
    return 0;
}