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


int a;
int b;
string s;
int main() {
	cin >> a >> b;
	cin >> s;
	for (int i = 0; i < s.size(); i++) {
		if (isdigit(s[i]) && i != a)continue;
		if (i == a&&s[i] == '-')continue;
		puts("No");
		return 0;
	}
	puts("Yes");
	return 0;
}