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

int main() {
	int a, b;
	string s;
	cin >> a >> b >> s;
	bool f = true;
	for (int i = 0; i < s.size(); i++) {
		if (i == a) {
			f &= s[i] == '-';
		} else {
			f &= '0' <= s[i] && s[i] <= '9';
		}
	}
	cout << (f ? "Yes" : "No") << endl;
	return 0;
}