Energy from SUNLIGHT + CO2(g) + H2O(l) = C6H12O6 (glucose) + O2(g)
The above is unbalanced, but it shows that sunlight is on the left side of the equation.
Sunlight provides the energy for the reaction to take place, without it nothing would really happen. Therefore it is an INPUT into the equation, thus it is on the left side. Outputs are placed on the right side of the equation.