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