#include <bits/stdc++.h>
using namespace std;

int main() {
  int A, B; cin >> A >> B;
  string S; cin >> S;
  
  bool can = true;
  if (int i=0; i<S.size(); i++) {
    if (i==A) { 
      if (S[i]!='-') can = false;
    }
    if (S[i] == '-') can = false;
  }
  if (can) cout << "Yes" << endl;
  else cout << "No" << endl;
}