#include<iostream>
using namespace std;
int main(void)
{
	int a,b,i;
	char s[10];
	cin>>a>>b>>s;
	for(i=0;i<a+b+1;i++) {
		if(i==a && s[i]!='-' || i!=a && s[i]=='-'){
			cout<<"No"<<endl;
			break;
		}
		if(i==a+b) cout<<"Yes"<<endl;
	}
	return 0;
}