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