#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  bool ok = s[a] == '-';
  for (int i = a + 1; i < a + b + 1; i++) {
    if (!(s[i] - '0' >= 0 && s[i] - '0' <= 9)) {
      ok = false;
      break;
    }
  }
  cout << (ok ? "Yes" : "No");
  return 0;
}
