#include <iostream> #include <vector> using namespace std; int main() { char ans; ans='T'; int t; cin>>t; vector<int> x(t+1); x[0]=0; for(int i=1;i<=t;i++){ cin>>x[i]; if(x[i]!=x[i-1]+1&&x[i]!=x[i-1]-1){ ans='F'; break; } } cout<<ans<<endl; }