#include <bits/stdc++.h> #pragma GCC optimize("O3,unroll-loops") #pragma GCC target("avx2") #define int long long #define pii pair<int,int> #define vi vector<int> #define ff first #define ss second #define sp << " " << #define all(x) x.begin(),x.end() #define big(x) ((int)(x.size())) using namespace std; const int MOD = 998244353, LIM = 1e6+1, inf = 2e18,N = 2e5+1; void solve() { int n,m,k; cin >> n >> m >> k; bitset<4100> bsts[n+1],bsts2[n+1]; vector<string> strs(n+1); stack<int> stk; for (int i=1;i<=n;i++) { cin >> strs[i]; for (int j = 0;j<m;j++) { bsts[i][j] = (strs[i][j] == 'A' || strs[i][j] == 'C'); bsts2[i][j] = (strs[i][j] == 'A' || strs[i][j] == 'G'); } } vector<vi> memo(n+1,vi(n+1,-1)); auto calcdiff =[&](int i,int j) -> int { if (i > j) swap(i,j); if (memo[i][j] != -1) return memo[i][j]; return memo[i][j] = ((bsts[i]^bsts[j])|(bsts2[i]^bsts2[j])).count(); }; for (int i=1;i<=n;i++) { int fl = 1; for (int j = 1;j<=n;j++) { if (i != j && calcdiff(i,j) != k) { fl = 0; break; } } if (fl) { cout << i << '\n'; return; } } } signed main() { ios_base::sync_with_stdio(0); cin.tie(0); int t = 1; //cin >> t; while (t --> 0) solve(); }