#include<bits/stdc++.h>
#define int long long
#define mod 998244353ll
#define pii pair<int,int>
#define fi first
#define se second
#define mems(x,y) memset(x,y,sizeof(x))
#define pb push_back
#define db double
using namespace std;
const int maxn=200010;
const int inf=1e18;
inline int read(){
	int x=0,f=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
	while(ch>='0'&&ch<='9'){x=(x<<3)+(x<<1)+(ch-48);ch=getchar();}
	return x*f;
}
bool Mbe;

int n,m,k;
char s[maxn],t[maxn];
void work(){
	n=read();m=read();k=read();
	scanf("%s",s+1);
	for(int i=1;i<=k;i++)t[i]=s[i];
	int p=0,q=0;
	for(int i=2;i<=m;i++){
		for(int j=(i-1)*k+1;j<=i*k;j++)if(s[j]!=t[j-(i-1)*k]){
			if(p){
				printf("1 1\n");
				return ;
			}
			p=1,q=i;
			break;
		}
	}
	for(int ii=2;ii<=n;ii++){
		scanf("%s",s+1);
		for(int i=1;i<=m;i++){
			for(int j=(i-1)*k+1;j<=i*k;j++)if(s[j]!=t[j-(i-1)*k]){
				if(p){
					printf("1 1\n");
					return ;
				}
				p=ii,q=i;
				break;
			}
		}
	}
	printf("%lld %lld\n",p,q);
}

// \
444

bool Med;
int T;
signed main(){
//	freopen(".in","r",stdin);
//	freopen(".out","w",stdout);
	
//	ios::sync_with_stdio(0);
//	cin.tie(0);cout.tie(0);
	
//	cerr<<(&Mbe-&Med)/1048576.0<<" MB\n";
	
	T=1;
	while(T--)work();
}