#include<iostream>
using namespace std;
int main(){
	int a,b;
	char ca[20];
	bool s=true;
	cin>>a>>b;
	cin>>ca;
	for(int i=0;i<a+b+1;i++){
		if(i==a){
			if(ca[i]!='-')s=false;
		}else if(ca[i]=='-')s=false;
	}
	if(s)cout<<"Yes"<<endl;
	else cout<<"No"<<endl;
	return 0;
}
