include<bits/stdc++.h>
using namespace std;
 
int main()
{
	string s;
	int a,b;
	
	cin>>a>>b;
	cin>>s;
	
	for(int i=0;i<=s.size();i++)
	{
		if(i==a)
		{
			if(s[i]!='-')
			{
				cout<<"No";
				return 0;
			}
		}
		else if(!isdigit(s[i]))  cout<<"No";
	}
	
	cout<<"Yes";
	return 0; 
}