#include <bits/stdc++.h>
using namespace std;


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