#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) {
  if (!b) return a;
  return gcd(b, a % b);
}
long long power(long long x, long long y, long long p) {
  long long res = 1;
  x %= p;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  {
    long long a, b, n, f = 0;
    cin >> a >> b;
    string s;
    cin >> s;
    n = s.length();
    if (s[a] == '-') {
      for (int i = a + 1; i < n; i++) {
        if (s[i] - '0' > 9 || s[i] - '0' < 0) {
          f = 1;
          break;
        }
      }
      if (f)
        cout << "No"
             << "\n";
      else
        cout << "Yes"
             << "\n";
    } else {
      cout << "No"
           << "\n";
    }
  }
  return 0;
}
