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