#https://yukicoder.me/problems/273

def main():
    import sys
    input = sys.stdin.readline
    sys.setrecursionlimit(10000000)
    from collections import Counter, deque
    #from collections import defaultdict
    from itertools import combinations, permutations, accumulate
    #from itertools import product
    from bisect import bisect_left,bisect_right
    import heapq
    from math import floor, ceil
    #from operator import itemgetter

    inf = 10**17
    #mod = 10**9 + 7

    sx,sy = map(float, input().split())
    N = int(input())
    dest = []
    #荷物の総重
    tw = 0
    for _ in range(N):
        x,y,w = map(float, input().split())
        tw += w
        dest.append([x, y, w])

    #dp[s][itme]:sは既に届けた荷物, itemは最後に届けた荷物
    #         dp[s][item]はそこから最適に届けたときにかかる時間
    dp = [[inf]*(N) for _ in range(1<<N)]
    for i in range(N):
        dp[0][i] = 0
    res = []

    for s in range(1<<N):
        #残りの荷物
        W = 0
        for i in range(N):
            if s&(1<<i):
                continue
            W += dest[i][2]
        T = (W+100)/120

        if s==(1<<N)-1:
            for i in range(N):
                res.append(dp[s][i]+T*(abs(dest[i][0]-sx)+abs(dest[i][1]-sy)))
        elif s==0:
            for i in range(N):
                ns = s|(1<<i)
                for j in range(N):
                    dp[ns][i] = min(dp[ns][i], dp[s][j]+T*(abs(dest[i][0]-sx)+abs(dest[i][1]-sy)))
        else:
            for i in range(N):
                if s&(1<<i):
                    continue
                ns = s|(1<<i)
                for j in range(N):
                    dp[ns][i] = min(dp[ns][i], dp[s][j]+T*(abs(dest[i][0]-dest[j][0])+abs(dest[i][1]-dest[j][1])))
    print(min(res)+tw)

if __name__ == '__main__':
    main()