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

int main(){
    int n;
    cin >> n;
    int a[n];
  	for ( int i = 0; i < n; i ++ ) {
    	cin >> a[i];
    }
  
    string ans = "T";
  
    for ( int i = 0; i < n-1; i++ ){
      int d = abs( a[i] - a[i+1] );
      if ( d != 1 ) ans = "F";
      
    }

    cout << ans << endl;
    return 0;
}