Study the information given below carefully, and answer the question that follow:
On a stage, D, N, A and P are standing as described below facing North.
1) N is 2.5 m to the west of A.
2) K is 4 m to the right of A.
3) D is 6 m to the south of K.
4) P is 9 m to the north of D.
If a boy walks from N, meets A followed by K, D and then P, how many metres has he walked if he has travelled the straight distance all through?