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