#include <iostream>
using namespace std;

int main()
{
	int a,b;
	cin>>a>>b;
	string s;
	cin>>s;
	for(int 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;
}