#include <bits/stdc++.h>   long n, m, x, y, i, a[1000], z;   double aa, bb, sum;   int main() {     scanf( %ld%ld , &n, &m);     for (i = 1; i <= n; i++) scanf( %ld , &a[i]);     sum = 0;     for (i = 1; i <= m; i++) {       scanf( %ld%ld%ld , &x, &y, &z);       aa = a[x] + a[y];       bb = z;       if (aa / bb > sum) {         sum = aa / bb;       }     }     printf( %0.15lf , sum);   }   