#include<iostream>
using namespace std;
int a,b;
string s;
int main()
{
	cin>>a>>b;
	cin>>s;
	if(s[a]=='-')
	{
		s.erase(a,1);
		int k=s.find("-");
		if(k==-1) cout<<"Yes";
		else cout<<"No"; 
	}
	else cout<<"No";
	return 0;
}