#include <iostream>
#include <string>

using namespace std;

int main()
{
	int a, b, cnt = 0;
	string s;
	cin >> a >> b >> s;
	for (int i = 0; i < a + b + 1; i++) {
		if (s[i] == '-') {
			cnt++;
		}
	}
	if (cnt == 1 && s[a] == '-') {
		cout << "Yes" << endl;
	}
	else {
		cout << "No" << endl;
	}
}

