Help me pls..

Lili gave 1/4 of her money to Simon. Then Simon gave 1/5 of whatever money he had then to Lili. Later Lili decided to give 1/3 of whatever money she had then to Simon. Finally, Lili had $688 and Simon had $872. How much did Simon have at first?

S1=1/4 L+So

L1=1/5 S1+3/4 Lo

2/3 L1=688
S1+1/3 L1=872
so solve these two for S1, L1 then to to the original equations and solve for So and Lo