#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B, size, num;
  num = 0;
  string S;
  cin >> A >> B >> S;
  size = S.length();
  if (size == A + B + 1) {
    for (int i = 0; i < size; i++) {
      if ((i == A + 1) && (S[i] == '-'))
        num++;
      else if ((0 <= S[i] && S[i] <= 9) && !(i == A + 1))
        num++;
    }
  }
  if (num == size)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
