#include<iostream>
#include<cstring>
using namespace std;
string c;
int main()
{
	int a,b;
	cin>>a>>b>>c;
	int l=c.size();
	for(int i=0;i<l;i++)
	{
		if((!(c[i]>='0'&&c[i]<='9')&&i!=a)||(i==a&&c[i]!='-'))
		{
			cout<<"No"<<endl;
			return 0;
		}
	}
	cout<<"Yes"<<endl;
	return 0;
}