#include <bits/stdc++.h>
using namespace std;
const long long int mod = 1e9 + 7;
const long long int inf = 1e18;
vector<long long int> fact;
long long int mpow(long long int base, long long int exp);
bool isPrime(long long int num);
bool isPowerTwo(long long int x);
bool isSubstring(string s1, string s2);
void factorial(long long int num);
void factmod(long long int num);
void primeFactor(long long int num);
void itzprasuk() {
  long long int n, p, q;
  cin >> n;
  p = 0, q = 0;
  long long int x, y;
  string s;
  while (n--) {
    cin >> x >> y;
    if (min(abs(p + x - q), abs(q + y - p)) == abs(p + x - q)) {
      s.push_back('A');
      p = p + x;
    } else {
      s.push_back('G');
      q = q + y;
    }
  }
  if (abs(p - q) <= 500)
    cout << s << "\n";
  else
    cout << "-1\n";
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long int T = clock();
  long long int t = 1;
  while (t--) {
    itzprasuk();
  }
  cerr << "TIME : " << 1000 * (double)(clock() - T) / CLOCKS_PER_SEC << " ms\n";
  T = clock();
  return 0;
}
long long int mpow(long long int base, long long int exp) {
  base %= mod;
  long long int result = 1;
  while (exp > 0) {
    if (exp & 1) result = ((long long int)result * base) % mod;
    base = ((long long int)base * base) % mod;
    exp >>= 1;
  }
  return result;
}
bool isPrime(long long int num) {
  if (num <= 1) return false;
  for (long long int i = 2; i * i <= num; i++)
    if (num % i == 0) return false;
  return true;
}
bool isPowerTwo(long long int x) { return (x && !(x & (x - 1))); }
bool isSubstring(string s1, string s2) {
  if (s1.find(s2) != string::npos)
    return true;
  else
    return false;
}
void factorial(long long int num) {
  fact[0] = 1;
  for (long long int i = 1; i <= num; i++) fact[i] = i * fact[i - 1];
}
void factmod(long long int num) {
  fact[0] = 1;
  for (long long int i = 1; i <= num; i++) fact[i] = (i * fact[i - 1]) % mod;
}
void primeFactor(long long int num) {
  for (long long int i = 2; i <= num; i++)
    if (num % i == 0) {
      long long int cnt = 0;
      while (num % i == 0) cnt++, num /= i;
      cout << i << "^" << cnt << " ";
    }
  if (num > 1)
    cout << num << "^"
         << "1"
         << " ";
}
