#include <bits/stdc++.h>
using namespace std;
#define int              long long int
#define double           long double
#define print(a)         for(auto x : a) cout << x << " "; cout << endl
 
 
const int M = 1000000007;
const int N = 3e5+9;
const int INF = 2e9+1;
const int LINF = 2000000000000000001;
 
inline int power(int a, int b, int mod=M) {
    int x = 1;
    a %= mod;
    while (b) {
        if (b & 1) x = (x * a) % mod; 
        a = (a * a) % mod;
        b >>= 1;
    }
    return x;
}
 
 
//_ ***************************** START Below *******************************
 
 
 
vector<int> a;
 
int consistency(int n, int k){
 
    for(int i=0; i<n; i++){
        a[i] += (i+1);
    }
 
    sort(begin(a), end(a));
 
 
    int i=0;
    while(k>=0 && i<n){
        k -= a[i];
        i++;
    }
 
    if(k<0) return i-1;
    return i;
 
}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
int practice(int n, int k){
 
 
    return 0;
}
 
 
 
 
 
void solve() {
 
    int n, k;
    cin>> n >> k;
 
    a.resize(n);
    for(int i=0; i<n; i++) cin >> a[i];
 
    cout << consistency(n, k) << endl;
 
 
}
 
 
 
 
 
int32_t main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
 
    int t = 1;
    cin >> t;
    while (t--) {
        solve();
    }
 
    return 0;
}

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10
5 6
1 1 1 1 1
8 32
100 52 13 6 9 4 100 35
1 1
5
4 5
4 3 2 1
5 9
2 3 1 4 1
5 8
2 3 1 4 1
4 3
2 3 4 1
4 9
5 4 3 3
2 14
7 5
5 600000000
500000000 400000000 300000000 200000000 100000000