#include <bits/stdc++.h> using namespace std; typedef signed long long ll; #undef _P #define _P(...) (void)printf(__VA_ARGS__) #define FOR(x,to) for(x=0;x<to;x++) #define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++) #define ALL(a) (a.begin()),(a.end()) #define ZERO(a) memset(a,0,sizeof(a)) #define MINUS(a) memset(a,0xff,sizeof(a)) //------------------------------------------------------- int N; int X[100],Y[100]; double W[100],TW; double dp[15][1<<15]; void solve() { int i,j,k,l,r,x,y; string s; cin>>X[0]>>Y[0]; cin>>N; FOR(i,N) cin>>X[i+1]>>Y[i+1]>>W[i+1], TW+=W[i+1]; N++; FOR(i,N) FOR(j,1<<N) dp[i][j]=1e15; dp[0][0]=0; for(int mask=0;mask<1<<N;mask++) { FOR(i,N) if(dp[i][mask]<1e15) { double lw=TW; FOR(j,N) if(mask&(1<<j)) lw-=W[j]; FOR(j,N) if((mask&(1<<j))==0) { int lo=abs(X[j]-X[i])+abs(Y[j]-Y[i]); dp[j][mask | (1<<j)] = min(dp[j][mask | (1<<j)], dp[i][mask] + lo*(lw+100.0)/120 + W[j]); } } } _P("%.12lf\n",dp[0][(1<<N)-1]); } int main(int argc,char** argv){ string s;int i; if(argc==1) ios::sync_with_stdio(false); FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin); solve(); return 0; }