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