#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  bool ans = true;
  if (a + b + 1 != s.size())
    ans = false;
  else {
    for (int i = 0; i < s.size(); i++) {
      if (i != a && isdigit(s[i]) == false) {
        ans = false;
        break;
      } else if (s[a] != '-')
        ans = false;
      break;
    }
  }
  cout << ((ans) ? "Yes" : "No") << endl;
}
