#include <bits/stdc++.h>
using namespace std;

int main() {
  int a, b; cin >> a >> b;
  string s; cin >> s;
  for (int i=0; i<a+b+1; ++i) {
    if ((i == a) ^ (s[i] == '-')) {
      cout << "No\n";
      return 0;
    }
  }
  cout << "Yes\n";
  return 0;
}
