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