Chroma — When Outrage Shaman enters the battlefield, it deals damage to target creature equal to the number of red mana symbols in the mana costs of permanents you control.
Chroma abilities check only mana costs, which are found in a card’s upper right corner. They don’t count mana symbols that appear in a card’s text box.
Chroma abilities count hybrid mana symbols of the appropriate color. For example, a card with mana cost {3}{U/R}{U/R} has two red mana symbols in its mana cost.
The effect counts the mana symbols in this cards mana cost as well.