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

