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