#include <bits/stdc++.h>
const int INF = 1e9;
const int MOD = 1e9 + 7;
const long long LINF = 1e18;
using namespace std;
int main() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  for (int i = 0; i < (int)(a + 1); i++) {
    if (i == a && s[i] != '-') {
      cout << "No" << endl;
      return 0;
    } else if (i != a && s[i] == '-') {
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
}
