A permutation p of length n is a sequence of distinct integers p 1 , p 2 , ..., p n (1 ≤ p i ≤ n ) . A permutation is an identity permutation, if for any i the following equation holds p i = i . A swap ( i , j ) is the operation that swaps elements p i and p j in the permutation. Let's assume that f ( p ) is the minimum number of swaps that you need to make the permutation p an identity permutation. Valera wonders, how he can transform permutation p into any permutation q , such that f ( q ) = m , using the minimum number of swaps. Help him do that. The first line contains integer n ( 1 ≤ n ≤ 3000 ) — the length of permutation p . The second line contains n distinct integers p 1 , p 2 , ..., p n ( 1 ≤ p i ≤ n ) — Valera's initial permutation. The last line contains integer m ( 0 ≤ m < n ). In the first line, print integer k — the minimum number of swaps. In the second line, print 2 k integers x 1 , x 2 , ..., x 2 k — the description of the swap sequence. The printed numbers show that you need to consecutively make swaps ( x 1 , x 2 ) , ( x 3 , x 4 ) , ..., ( x 2 k - 1 , x 2 k ) . If there are multiple sequence swaps of the minimum length, print the lexicographically minimum one. Sequence x 1 , x 2 , ..., x s is lexicographically smaller than sequence y 1 , y 2 , ..., y s , if there is such integer r (1 ≤ r ≤ s ) , that x 1 = y 1 , x 2 = y 2 , ..., x r - 1 = y r - 1 and x r < y r .