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