
#include <iostream>
using namespace std;

int main() {
	int a,b;
	cin>>a>>b;
	char s[a+b+1];
	cin>>s;
	bool flag=1;
	for(int i=0;i<a+b+1;i++){
		if(i==a){
			if(s[i]!='-') flag=0;
		}else{
			if(s[i]=='-') flag=0;
		}
	}
	if(flag){
		cout<<"Yes"<<endl;
	}else{
		cout<<"No"<<endl;
	}
	return 0;
}
