without iteration condition, =A1+C1 in C1 cell,

I've tried iteration condition, but it is not taking only the 'A1' value, if I put some value in some other cell, C1 is calculating like =A1+C1 in C1 cell,means A1 value is 5, in C1 i put this farmula =A1+C1, its coming 0, After Iteration condition active, in C1 value will come 5, if i enter in B9 some other value, in C1 result wil come 10,