#include<bits/stdc++.h>
#define FIO(file) freopen(file".in","r",stdin),freopen(file".out","w",stdout)
using namespace std;
const int N=2e5+5;
const int inf=1e9+7;

static char buf[1000000],*p1=buf,*p2=buf;
#define getchar() p1==p2&&(p2=(p1=buf)+fread(buf,1,1000000,stdin),p1==p2)?EOF:*p1++
inline int wrd(){int x=0,f=1;char c=getchar();while(c<'0' || c>'9'){if(c=='-') f=-1;c=getchar();}while(c>='0' && c<='9') {x=(x<<3)+(x<<1)+c-48;c=getchar();}return x*f;}
inline void write(int x){static char buf[20];static int len=-1;if(x<0)putchar('-'),x=-x;do buf[++len]=x%10,x/=10;while(x);while(len>=0)putchar(buf[len--]+48);}

int n,m,k,cnt;
string s,a[205][205];

signed main(){
	cin.tie(nullptr)->sync_with_stdio(false);
	cin>>n>>m>>k;
	for(int i=1;i<=n;++i){
		cin>>s;
		for(int j=0;j+k-1<m*k;j+=k){
			for(int p=j;p<j+k;++p) a[i][j/k+1]+=s[p];
		}
	}
	int p(0),q(0);
	for(int i=1;i<=n;++i){
		for(int j=1;j<=m;++j){
			if(a[i][j]!=a[1][1]){
				if(!p) p=i,q=j;
				else cout<<"1 1",exit(0);
			}
		}
	}
	cout<<p<<' '<<q;
}