For problem statement at 1000-1999/1200-1299/1270-1279/1272/problemC.txt this is a correct solution, but verifier at 1000-1999/1200-1299/1270-1279/1272/verifierC.go ends with Accepted can you fix the verifier? ```go
package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	in := bufio.NewReaderSize(os.Stdin, 1<<20)

	var n, k int
	fmt.Fscan(in, &n, &k)

	var s string
	fmt.Fscan(in, &s)

	allowed := make([]bool, 26)
	for i := 0; i < k; i++ {
		var c string
		fmt.Fscan(in, &c)
		allowed[c[0]-'a'] = true
	}

	var ans int64
	var cur int64

	for i := 0; i < n; i++ {
		if allowed[s[i]-'a'] {
			cur++
		} else {
			ans += cur * (cur + 1) / 2
			cur = 0
		}
	}
	ans += cur * (cur + 1) / 2

	fmt.Println(ans)
}
```