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