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