#include <bits/stdc++.h>

using namespace std;
typedef pair<int, char> P;

int main() {
  int t;
  cin >> t;
  int prev = 0;
  bool good = true;
  while (t--) {
    int x;
    cin >> x;
    if (abs(x - prev) != 1) good = false;
    prev = x;
  }
  cout << (good? 'T': 'F') << '\n';
  return 0;
}