#include<cstdio>#include<algorithm>usingnamespace std;int t, n, k, num, ans;intmain(){scanf("%d",&t);while(t--){scanf("%d%d%d",&n,&k,&ans);for(int i =2; i <= n; i++){scanf("%d",&num);if(k /(i -1)<=0)continue;//不够移动了 int c =min(k /(i -1), num);//能移动多少到第一个
ans += c; k -= c *(i -1);}printf("%d\n", ans);}return0;}