#include <iostream>
#include <string>
using namespace std;
int main() {
	int a,b,i,x=0,y=0,f=0;
	string s;
	cin >> a >> b >> s;
	for(i=0;i<s.size();i++) {
		if(a[i]=='-')
			f=1;
		else if(f==0)
			x++;
		else
			y++;
	}
	if(x==a && y==b)
		cout << "Yes" << endl;
	else
		cout << "No" << endl;
	return 0;
}
