#include<bits/stdc++.h>
#define ll long long
#define db double
#define ins push_back
#define mk make_pair
using namespace std;
const int N = 1e6+7;
const ll mod = 1e9+7;
template <typename T> inline void read(T &x){
	T ch=getchar(),xx=1;x=0;
	while(!isdigit(ch)) xx=ch=='-'?-1:xx,ch=getchar();
	while(isdigit(ch)) x=(x<<1)+(x<<3)+ch-'0',ch=getchar();
	x*=xx;
}
template <typename T> void print(T x){
	if(x<0) putchar('-'),x=-x;
	if(x>9) print(x/10);
	putchar(x%10+'0');
}
string s;
vector <int> e[N];
int main(){
	int n,m,k;
	read(n),read(m),read(k);
	m=m*k;
	for(int i=0;i<n;i++){
		cin>>s;
		e[i].push_back(0); 
		for(int j=k;j<m;j+=k){
			int l=j-1 -k + 1;
			bool f=1;
			for(int r=0;r<k;++r) 
				if(s[l+r]!=s[j+r]) f=0;
			if(!f) e[i].push_back(1);
	    	else e[i].push_back(0);	
		}
	}
	m=m/k;
//	for(int i=0;i<n;++i,cout<<endl)
//		for(int j=0;j<m;++j) 
//			cout<<e[i][j]<<" ";
		
	for(int i=0;i<n;++i){
		for(int j=1;j<m-1;++j){
			if(e[i][j]==1 && e[i][j+1]==1){
				print(i+1),putchar(' ');
				print(j+1);return 0;
			}
		}
	}
	for(int i=0;i<n;++i){
		for(int j=1;j<m-1;++j){
			if(e[i][j]==1){
				print(i+1),putchar(' ');
				print(j);return 0;
			}
			if(e[i][j+1]==1){
				print(i+1),putchar(' ');
				print(j+2);return 0;
			}
		}
	}
	return 0;
}
/*
3 5 3
QWQQWQQWQQWQQWQ
QWQQWQQWQQWQQWQ
QWQQWQQWQQWQQwQ
*/