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