Codeforces[div.2-706]-A. Beru-taxi

#include <bits/stdc++.h>
using namespace std;

int main() {
 int n,p,i,j,lo=0,q,a[100001],t=0,a1,b,x,z,y;
 double k ,l = 1e99;
     cin >> a1>>b>>n;
     for(i=1;i<=n;i++){
      cin >>x>>y>>z;
      k =  hypot(x - a1 + 0., y - b + 0.) / z;
      l = min(l,k);
     }
     printf("%.10f\n",l);
 return 0;
}