package main

import "fmt"

func main(){
	var A, B int
	var S string
	var ans int

	fmt.Scan(&A, &B, &S)

	if S[A] == '-'{
		ans++
	}
	for i := 0 ; i < A + B + 1 ; i++ {
		if '0' <= S[i]	&& S[i] <= '9' {
			ans++
		}
	}
	if ans == A + B + 1{
		fmt.Println("Yes")
	}else{
		fmt.Println("No")
	}
}