#include <iostream>
#include <cstdio>
#include <cctype>
using namespace std;

int main()
{
	string s;
	int a,b,i;
	cin>>a>>b;
	cin>>s;
	
	if(a+b+1!=s.size())
	{
		cout<<"No"<<endl;
		return 0;
	}
	for(i=0;i<s.size();i++){
	{
		if(i!=a)
		if(!isdigit(s[i])){
		cout<<"No"<<endl;
		return 0;}
	}
	else
	if('-'!=s[i]){
	cout<<"No"<<endl;
	return 0;}}
	
	cout<<"Yes"<<endl;
	return 0;
}