Train #2
Contest Problems
Problem Tasks
# Date State
Not Contest
# Date State

C. Matritsa8

Time limit : 1000 ms
Memory limit : 64 mb

Kvadrat matritsani $m$ soniga qoldiqsiz bo`linadigan elementlarini o`rtacha qiymati xisoblansin.

Kiruvchi ma`lumotlar: Birinchi satrda $n$ ($1\le n \le 50$). Keyingi $n$ ta satrda $n$ ta butun son matritsa elementlari ($-100\le a[i][j] \le 100$). Keyingi satrda $m$ berilgan.($1\le m \le 50$)

Chiquvchi ma`lumotlar: Masala yechimi $10^{-2}$ aniqlikda chiqarilsin.

Input
4
52 70 -14 28
88 -15 19 -65
76 53 -60 27
45 -95 70 -98
3
Output
-0.75
Input
9
33 77 -40 27 45 -93 51 95 -3
35 -3 90 -11 96 -16 56 -59 38
80 44 -47 54 62 -74 68 61 -68
51 -56 24 -6 98 -78 30 -30 35
99 89 -65 30 8 -83 4 48 0
55 -33 14 -79 31 -44 33 -41 95
97 39 -96 93 44 -61 80 83 -28
36 -65 34 -26 21 -29 27 -21 45
12 73 -64 46 5 -82 84 14 -62
8
Output
9.23