#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
using ll = long long ;
using P = pair<int,int> ;
using pll = pair<long long,long long>;
constexpr int INF = 1e9;
constexpr long long LINF = 1e17;
constexpr int MOD = 1000000007;
constexpr double PI = 3.14159265358979323846;

int main(){
    int t;
    cin >> t;
    bool ok = true;
    vector<int> a(t);
    rep(i,t){
        cin >> a[i];
        if(i==0){
            if(a[i]!=-1&&a[i]!=1) ok = false;
        }else
        {
            if(abs(a[i]-a[i-1])!=1) ok = false;
        }
    }
    cout << (ok?'T':'F') << endl;
    return 0;
}