#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  getchar();
  for (int i = 1; i <= a + b + 1; i++) {
    char p = getchar();
    if (i == a + 1) {
      if (p != '-') {
        cout << "No\n";
        return 0;
      }
    } else {
      if (!((p) >= '0' && (p) <= 9)) {
        cout << "No\n";
        return 0;
      }
    }
  }
  cout << "Yes\n";
  return 0;
}
