#include<iostream>
using namespace std;

char s[30];

int main(){
	int a,b; cin>>a>>b;
	cin>>s;
	if(s[a]!='-') { cout<<"No"<<endl; return 0; }
	else{
		for(int i=0;i<=a+b;i++)
			if(i!=a&&(s[i]<'0'||s[i]>'9')) { cout<<"No"<<endl; return 0; }
	}
	cout<<"Yes"<<endl;
	return 0;
}