#include <bits/stdc++.h>
using namespace std;
int main () {
	int a,b;
	string s;
	cin >> a >> b;
	cin >> s;
	bool b = true;
	for (int i = 0; i < (int)s.size(); ++i)
	{
		if(i < a){
			if((int)(s[i] - '0') > 9 && (int)(s[i] - '0') < 0){
				b = false;
			}
		}else if(i == a){
			if(s[a] != '-')b = false;
		}else{
			if((int)(s[i] - '0') > 9 && (int)(s[i] - '0') < 0){
				b = false;
			}
		}
	}
	if(b){
		cout << "Yes" << endl;
	}else{
		cout << "No" << endl;
	}
}