#include<bits/stdc++.h>
#define inf 1e9
#define eps 1e-6
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define REP(i,a,b) for(int i=a;i>=b;i--)
#define pb push_back
#define fr first
#define sd second
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
inline ll read()
{
	char ch = getchar();
	ll s = 0,w = 1;
	while(ch < '0' || ch > '9'){if(ch == '-') w = -1; ch = getchar();}
	while(ch >= '0' && ch <= '9'){s = s * 10 + ch -'0'; ch = getchar();}
	return s * w;
}
int number(char c)
{
	if(c == 'A') return 1;
	if(c == 'T') return 2;
	if(c == 'C') return 3;
	if(c == 'G') return 4;
	exit(-1);
}
const int mod = 998244353, seed = 131;
int n;
int ksm(int a, int b)
{
	int ans = 1;
	while(b){if(b & 1)ans=1LL*ans*a%mod;b >>= 1; a=1LL*a*a%mod;}
	return ans;
}
#define N 110
int H[N], h[N], invH[N];
int a[N]; char s[N];
int ck(int l1,int r1,int l2,int r2)
{
	int w1 = (h[r1] + mod - h[l1 - 1])%mod;
	int w2 = (h[r2] + mod - h[l2 - 1])%mod;
	return (1LL*w2*invH[l2-l1]%mod==w1);
}
int sol(int l,int r)
{
	int ans = 1, len = r - l + 1;
	int t = r + 1;
	FOR(i,r+1,n-len+1)if(i >= t)
	{
		if(ck(l,r,i,i+len-1)){ans ++;t = i + len;}
	}
	return ans;
}
void sol()
{
	scanf("%s",s+1);
	n = strlen(s+1);
	FOR(i,1,n)a[i]=number(s[i]);
	H[0] = 1; FOR(i,1,n)H[i] = 1LL * H[i-1] * seed % mod;
	invH[n]=ksm(H[n],mod-2);REP(i,n-1,0)invH[i]=1LL * invH[i+1] * seed % mod;
	FOR(i,1,n)h[i] = (h[i-1] + 1LL * a[i] * H[i] % mod)%mod;
	int L = inf, R = inf, mx = 0;
	FOR(l,1,n)FOR(r,l,n)
	{
		int num = sol(l,r);
		if(num >= 2 && r - l + 1 > R - L + 1)L = l, R = r, mx = num;
	}
	FOR(i,L,R)cout<<s[i];cout << '\n';
}
signed main()
{
	int T = read();
	while(T --) sol();	
	return 0;
}