#include<bits/stdc++.h>
using namespace std;

int main(){
	int a,b;
	string s;
	cin>>a>>b>>s;

	if(s[a]!='-'){
		cout<<"No"<<endl;
		return 0;
	}

	for (int i = 0; i < a+b+1; i++){
		if(i==a)continue;
		if(s[i]<'0'||s[i]>'9'){
			cout<<"No"<<endl;
			return 0;
		}
	}

	cout<<"Yes"<<endl;

}
