#include<bits/stdc++.h>
using namespace std;
#define lo long long
#define sr string
#define ch char
#define ve vector
#define al(x) x.begin(),x.end()
#define sort(x) sort(x.begin(),x.end())
#define reverse(x) reverse(x.begin(),x.end())
#define rep(i,a) for(lo i=0;i<a;i++)
#define lep(i,a) for(lo i=0;i<=a;i++)
#define rrep(i,a,b) for(lo i=a;i<b;i++)
#define rrrep(i,a,b) for(lo i=a;i>=b;i--)
#define wh while

int main(){
    lo n;
    cin>>n;
    ve<lo> num(n);
    bool frag=true;
    rep(i,n){
        cin>>num[i];
        if(i>=1){
            if(abs(num[i]-num[i-1])!=1){
                frag=false;
                break;
            }
        }
        if(abs(num[0])!=1){
            frag=false;
            break;
        }
    }
    if(frag){
        cout<<'T'<<endl;
    }
    else{
        cout<<'F'<<endl;
    }
    
}