a sequence a_1 a_2 dot a_k call arithmetic progression 1 k element satisfy condition a_i a_1 c cdot 1 fix cFor example sequence arithmetic progression 5 7 9 11 101 101 100 99 13 97 5 5 5 5 5 and sequence are not arithmetic progression 3 1 2 1 2 4 8 1 1 1 1 1 2 3 3 3you give sequence integer b_1 b_2 dot b_n find index j 1 le j le n delete b_j sequence reorder remain n1 element arithmetic progression if index output number 1