#include <bits/stdc++.h>

using namespace std;

int main()
{
	int a, b;
	string s;
	cin >> a >> b >> s;
	bool r = s[a] == '-';
	for (int i = 0; i < s.length(); i++)
		if (i != a)
			r = r&&isdigit(s[i]);
	cout << (r ? "Yes" : "No") << endl;
	return 0;
}
