import std.algorithm, std.container, std.conv, std.math, std.range, std.typecons, std.stdio, std.string;

auto rdsp(){return readln.splitter;}
void pick(R,T)(ref R r,ref T t){t=r.front.to!T;r.popFront;}
void readV(T...)(ref T t){auto r=rdsp;foreach(ref v;t)pick(r,v);}
void readC(T...)(size_t n,ref T t){foreach(ref v;t)v=new typeof(v)(n);foreach(i;0..n){auto r=rdsp;foreach(ref v;t)pick(r,v[i]);}}

void main()
{
  int t; readV(t);
  int[] x; readC(t, x);

  auto calc()
  {
    if (x[0].abs != 1) return false;
    foreach (i; 0..t-1)
      if ((x[i]-x[i+1]).abs != 1) return false;
    return true;
  }

  writeln(calc ? "T" : "F");
}