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