package main

import (
	"os"
	"sort"
)

func main() {
	buf := make([]byte, 8192)
	var pos, length int

	readByte := func() byte {
		if pos >= length {
			pos = 0
			var err error
			length, err = os.Stdin.Read(buf)
			if err != nil || length == 0 {
				return 0
			}
		}
		res := buf[pos]
		pos++
		return res
	}

	readInt := func() int {
		var res int
		b := readByte()
		for b <= 32 {
			if b == 0 {
				return 0
			}
			b = readByte()
		}
		for b > 32 {
			res = res*10 + int(b-'0')
			b = readByte()
		}
		return res
	}

	readInt64 := func() int64 {
		var res int64
		b := readByte()
		for b <= 32 {
			if b == 0 {
				return 0
			}
			b = readByte()
		}
		for b > 32 {
			res = res*10 + int64(b-'0')
			b = readByte()
		}
		return res
	}

	t := readInt()
	if t == 0 {
		return
	}

	out := make([]byte, 0, 1<<16)
	writeInt := func(v int) {
		if v == 0 {
			out = append(out, '0')
		} else {
			var tmp [20]byte
			idx := 20
			for v > 0 {
				idx--
				tmp[idx] = byte(v%10 + '0')
				v /= 10
			}
			out = append(out, tmp[idx:]...)
		}
		out = append(out, '\n')
		if len(out) > 1<<15 {
			os.Stdout.Write(out)
			out = out[:0]
		}
	}

	for tc := 0; tc < t; tc++ {
		n := readInt()
		c := readInt64()
		costs := make([]int, n)
		for i := 0; i < n; i++ {
			costs[i] = readInt() + i + 1
		}
		
		sort.Ints(costs)
		
		ans := 0
		var sum int64 = 0
		for i := 0; i < n; i++ {
			if sum+int64(costs[i]) <= c {
				sum += int64(costs[i])
				ans++
			} else {
				break
			}
		}
		writeInt(ans)
	}
	
	if len(out) > 0 {
		os.Stdout.Write(out)
	}
}