#include <bits/stdc++.h>
#define rep(i, ss, ee) for (int i = ss; i < ee; ++i)
using namespace std;

void solve() {
  int N, a = 0, b;
  string ans = "T";
  cin >> N;
  rep(i, 0, N) {
    cin >> b;
    if (abs(a - b) != 1) {
      ans = "F";
      break;
    }
    a = b;
  }
  cout << ans << endl;
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  solve();
  getchar();
}