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