#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  string ans = "Yes";
  if (s[a] != '-') ans = "No";
  for (int i = 0; i < a + b + 1 && i != a; i++) {
    if (s[i] != 0, 1, 2, 3, 4, 5, 6, 7, 8, 9) {
      ans = "No";
      if (i == a - 1) {
        i++;
      }
    }
  }
  cout << ans << endl;
}
