#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  int i = 1;
  int ans = 0;
  for (auto v : s) {
    if (i <= a || (a + 2 <= i && i <= a + b + 1)) {
      i++;
      if (v < '0' || v > '9') {
        ans++;
      }
    }
    if (i == a + 1) {
      i++;
      if (v != '-') {
        ans++;
      }
    } else {
      ans++;
      break;
    }
  }
  if (ans > 0) {
    cout << "No" << endl;
  } else {
    cout << "Yes" << endl;
  }
  return 0;
}
