#include <bits/stdc++.h>

using namespace std;
using llong = long long;
using P = pair<llong, llong>;

#define BE(x) x.begin(), x.end()

const llong inf = llong(1e18)+7;
const llong mod = 1e9+7;

int main(){
	int a,b;
	string s;

	cin >> a >> b >> s;
	bool check = true;
	for(int i = 0; i < a+b+1){
		if(i == a){
			if(s[a] != '-')
				check = false;
		}else
			if(s[i] == '-')
				check = false;

	}

	if(check)
		cout << "Yes" << endl;
	else
		cout << "No" << endl;

	return 0;
}