gets
current_x = gets.to_i
if current_x == 0 || current_x.abs >= 2
    puts "F"
    return
end

while l=gets
    move_x = l.to_i
    if (move_x.abs - current_x.abs).abs != 1
        puts "F"
        return
    end
    current_x = move_x
end

puts "T"