#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define mt make_tuple
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
#define pb push_back
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int N, cur=0,nex;
    cin >> N;
    rep(i, N) {
        cin >> nex;
        if (abs(cur - nex) != 1) {
            cout << "F" << endl;
            return 0;
        }
        cur = nex;
    }

    cout << "T" << endl;
}