#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  int a, b;
  cin >> a >> b >> s;
  if (s[a] != 45 || s.size() != a + b + 1) {
    cout << "No" << endl;
    return 0;
  } else {
    s[a] = 50;
  }
  for (int i = 0; i < a + b + 1; i++) {
    if (48 <= s[i] || s[i] <= 57) {
      continue;
    } else {
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
  return 0;
}
