#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  int d = 0;
  int m = 0, m1 = 0;
  string s;
  cin >> a >> b >> s;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] == '0') m1++;
  }
  for (int i = 0; i < s.size(); i++) {
    if (s[i] == '-') m++;
  }
  for (int i = 0; i < s.size(); i++) {
    if (s[i] == '0' || s[i] == '1' || s[i] == '2' || s[i] == '3' ||
        s[i] == '4' || s[i] == '5' || s[i] == '6' || s[i] == '7' ||
        s[i] == '8' || s[i] == '9')
      continue;
    else
      d++;
  }
  if (s[a] == '-' && s.size() == (a + b + 1) && a >= 1 && a <= 5 && b > 1 &&
      b <= 5 && m <= 1 && (d - 1) == 0 && m > 1)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
