// #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
int main() {
    // Input
    int T;
    cin >> T;
    vector<int> x(T+1);
    rep(i, T) cin >> x[i+1];

    // Judge
    bool ok = true;
    rep(i, T) if (abs(x[i+1] - x[i]) != 1) ok = false;

    // Output
    cout << (ok ? 'T' : 'F') << endl;
}