#include <iostream>
#include <vector>
#include <map>
#include<string>
#include<queue>
#include<math.h>
#define all(x) begin(x),end(x)
#define ll long long
#define P pair<int,int>
#define lP pait<ll,ll>
using namespace std;
int main() {
    int t=0;
    cin>>t;
    bool f=0;
    vector<int> a(t);
    for (int i=0;i<t;i++){
        cin>>a[i];
    }
    if(t==1 and a[0]!=1 and a[0]!=-1) f=1;
    for (int i=0;i<t-1;i++){
        if(abs(a[i]-a[i+1])!=1) f=1;
        else if(a[i]==a[i+1]) f=1;
        
    }
   
if(f) cout<<'F'<<endl;
else cout<<'T'<<endl;
    return 0;
}