#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int n, a, p;
bool f = 1;

int main()
{
    cin >> n;
    for (int i = 0; i < n; i++)
    {
        cin >> p;
        if (abs(a - p) != 1)
            f = 0;
        a = p;
    }
    cout << (f ? 'T' : 'F') << endl;
}