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