#include <iostream>
#include <string>
#include <math.h>
using namespace std;

int main()
{
	string ans="T";
	int t;
	cin >> t;
	int x[101];
	x[0] = 0;
	for (int i = 1; i < t+1; ++i)
	{
		cin >> x[i];
		if (abs(x[i] - x[i - 1] )!= 1) ans="F";

	}
    cout << ans << endl;

	fflush (stdin);
	getchar ();
	fflush (stdin);
	getchar ();
	return 0;
}