For problem statement at 1000-1999/1400-1499/1430-1439/1430/problemE.txt this is a correct solution, but verifier at 1000-1999/1400-1499/1430-1439/1430/verifierE.go ends with All tests passed can you fix the verifier? ```go
package main
import (
"bufio"
"fmt"
"os"
"strconv"
"strings"
)
type Fenwick struct {
tree []int
n int
}
func NewFenwick(n int) *Fenwick {
return &Fenwick{
tree: make([]int, n+2),
n: n,
}
}
func (f *Fenwick) Update(i, delta int) {
for i <= f.n {
f.tree[i] += delta
i += i & -i
}
}
func (f *Fenwick) Query(i int) int {
res := 0
for i > 0 {
res += f.tree[i]
i -= i & -i
}
return res
}
func main() {
reader := bufio.NewReader(os.Stdin)
line, _ := reader.ReadString('\n')
n, _ := strconv.Atoi(strings.TrimSpace(line))
s, _ := reader.ReadString('\n')
s = strings.TrimSpace(s)
pos := make([][]int, 26)
for i := 0; i < n; i++ {
c := s[i] - 'a'
pos[c] = append(pos[c], i)
}
p := make([]int, n)
ptr := make([]int, 26)
for i := 0; i < n; i++ {
c := s[n-1-i] - 'a'
p[i] = pos[c][ptr[c]] + 1
ptr[c]++
}
ft := NewFenwick(n)
var ans int64
for i := n - 1; i >= 0; i-- {
ans += int64(ft.Query(p[i] - 1))
ft.Update(p[i], 1)
}
fmt.Println(ans)
}
```