#include<iostream>
using namespace std;
int main() {
	string s;
	int a,b;
	cin>>a>>b>>s;
	for (int i=0,len=s.size();i<len;++i) {
		if (i!=a&&(s[i]>'9'||s[i]<'0')) return cout<<"No"<<endl,0;
		if (i==a&&s[i]!='-') return cout<<"No"<<endl,0;
	}
	cout<<"Yes"<<endl;
	return 0;
}