#include <bits/stdc++.h>
using namespace std;
string st;
long long n, m, zs, s;
int main() {
  cin >> n >> m;
  cin >> st;
  for (int i = 0; i < st.size(); i++)
    if (st[i] >= '0' && st[i] <= '9')
      zs++;
    else if (i == n && st[i] == '-') {
      cout << "Yes" << endl;
      return 0;
    } else {
      cout << "No" << endl;
      return 0;
    }
  cout << "No" << endl;
  return 0;
}
