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