#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B;
  string S, ret, haihun, Ans;
  cin >> A >> B >> S;
  for (int i = 1; i <= A + B + 1; i++) {
    ret = S[i];
    haihun = "-";
    if (ret == haihun && i == A + 1)
      Ans = "Yes";
    else {
      Ans = "No";
      break;
    }
  }
  cout << Ans;
}
