#include <iostream>
using namespace std;

int main() {
	int A, B;
	string S;
	cin >> A >> B >> S;
	for (int i = 0; i < A + B + 1; i++) {
		if (((i<A - 1 || i>A) && (S[i] == '-')) || (i == A && S[i] != '-')) {
			cout << "No" << endl;
			return 0;
		}
	}
	cout << "Yes" << endl;
}