oh exam Madoka get hard problemgiven integer n m pair integer v_i u_i also array b_1 b_2 ldots b_n initially fill zerosThen index 1 leq leq m perform b_v_i b_v_i 1 b_u_i b_u_i 1 b_v_i b_v_i 1 b_u_i b_u_i 1 note exactly operation perform iAlso array s length n consist 0 1 and array a_1 a_2 ldot a_n guarantee s_i 0 hold a_i 0help Madoka determine possible perform operation way s_i 1 hold a_i b_i if possible provide Madoka way perform operation