#include <bits/stdc++.h>
using namespace std;

int main(void) {
  int a, b;
  string s;
  bool f = true;
  cin >> a >> b >> s;
  for (int i = 0; i < s.length(); ++i) {
    if (i < a or i > a) {
      if (s[i] >= '0' and s[i] <= '9') else f = false;
    }
    else if (i == a) {
      if (s[i] == '-') else f = false;
    }
  }
  cout << (f ? "Yes" : "No") << endl;
}
      