#include<bits/stdc++.h>
using namespace std;
template<typename T>
void read(T &a){
	#define gc getchar()
	char c;a=0;int f=1;
	while(!isdigit(c=gc))if(c=='-')f=-1;
	do a=a*10+c-'0';
	while(isdigit(c=gc));
	a*=f;
}
template<typename T>
void write(T a){
	if(a<0)putchar('-'),a=-a;
	if(a>=10)write(a/10);
	putchar('0'+a%10);
}
typedef long long ll;
typedef long double ld;
mt19937_64 eg;
int n,m,k;
const int N=1e5+10;
string s[N];
using ull=unsigned long long;
ull a[N];const ll P=1000000000000000003;
ull b[N][4];
int main(){
	eg.seed(chrono::system_clock::now().time_since_epoch().count());
	cin>>n>>m>>k;
	for(int i=1;i<=n;++i)cin>>s[i];
	ull target=0;
	for(int i=1;i<=n;++i)a[i]=eg()%P,target+=a[i]*(m-k);
	for(int i=1;i<=n;++i)
		for(int j=0;j<m;++j)
			b[j][s[i][j]-'A']+=a[i];
	for(int i=1;i<=n;++i){
		ull tmp=0;
		for(int j=0;j<m;++j)
			tmp+=b[j][s[i][j]-'A'];
		// printf("%llu %llu\n",tmp,target);
		if(tmp-a[i]*m==target-a[i]*(m-k))printf("%d\n",i);
	}
	return 0;
}