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