#include "bits/stdc++.h" using namespace std; using ll = long long; using ld = long double; const int INF = (1 << 30) - 1; const ll INF64 = ((ll)1 << 62) - 1; const double PI = 3.1415926535897932384626433832795; const int dx[] = { -1, 0, 1, 0 }; const int dy[] = { 0, 1, 0, -1 }; int gcd(int x, int y) { return y ? gcd(y, x % y) : x; } ll gcd(ll x, ll y) { return y ? gcd(y, x % y) : x; } int lcm(int x, int y) { return x / gcd(x, y) * y; } ll lcm(ll x, ll y) { return x / gcd(x, y) * y; } bool solve(vector x) { for (int i = 0; i < x.size() - 1; i++) { if (abs(x[i] - x[i + 1]) != 1) { return false; } } return true; } int main() { ios::sync_with_stdio(false); cin.tie(0); int t; cin >> t; vector x; x.push_back(0); for (int i = 0; i < t; i++) { int pos; cin >> pos; x.push_back(pos); } cout << (solve(x) ? "T" :"F") << endl; return 0; }