#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i<(n); ++i)
using namespace std;
using ll=long long;
int main(){
    int t;
    cin>>t;
    vector<int>x(t);
    int cnt=0;
    bool ok=true;
    rep(i,t){
        cin>>x[i];
        if(x[i]!=cnt+1&&x[i]!=cnt-1)ok=false;
        cnt=x[i];
    }
    cout<<(ok==true?"T":"F")<<endl;
}