#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define int long #define ll long long #define rng(i,a,b) for(int i=int(a);i=int(a);i--) #define per(i,b) gnr(i,0,b) #define eb emplace_back #define all(x) x.begin(),x.end() #define SZ(x) x.size() #define fi first #define se second const int INF = 1e9; using namespace std; template using vc=vector; template using vvc=vc>; using pi=pair; using vi=vc; template inline bool chmax(T &a,T b){if(a inline bool chmin(T &a,T b){if(a>b){a=b;return true;}return false;} signed main() { cin.tie(0); ios::sync_with_stdio(0); cout<> N; int A[N]; rep(i,N) cin >> A[i]; bool frag=true; if(abs(A[0]-0)!=1) frag=false; rep(i,N-1){ if(abs(A[i+1]-A[i])!=1) frag=false; } if(frag) cout << 'T' << endl; else cout << 'F' << endl; }